****************************************************************************** From: "A.L. McCormack" Subject: Anybody out there? Date: 12 Jun 1995 19:44:31 GMT Organization: UW Is anybody out there? I am getting ready to do H-D exchange of a protein followed by micro-LC-ESI. Anyone have any general hints or suggestions? Thanks. Ashley L. McCormack, PhD UW ****************************************************************************** ****************************************************************************** Date: Mon, 12 Jun 1995 19:25:16 -0400 From: kmurray@emory.edu (Kermit K. Murray) Subject: Thanks David Bostwick! I think that one of the first threads on this new group should be a thank you to David Bostwick who got sci.techniques.mass-spec going. Thanks Dave! K. Murray --------------------------------------------------------------------- Kermit K. Murray Of. 404-727-2254 Emory University Lab 404-727-6534 Department of Chemistry Fax 404-727-6586 Atlanta, GA 30322 http://tswww.cc.emory.edu/~kmurray/ kmurray@emory.edu --------------------------------------------------------------------- ****************************************************************************** ****************************************************************************** From: mcbrp@leonis.nus.sg (Philp Robin John) Subject: Peptide/Protein ionisation? Date: 13 Jun 1995 03:40:01 GMT Organization: National University of Singapore Greetings to all, I do not have a background in mass-spec but do get a few samples of peptides and small proteins analysed by LC/MS to complement analysis by conventional Edman chemistry in the determination of amino acid sequenece.I usually carry out proteolytic digestion of proteins and separate subsequent peptides by microbore LC before sequencing the peptides. When I have taken some of the collected peptide for LC/MS or direct flow/MS analysis I only get about a 50% success rate in forming an ion. One suggestion has been that I use trifluoroacetic acid(TFA) at 0.08% in my LC solvents and this may be suppressing the ionisation and that it is better to use formic acid. Does anybody know of any comparisons of ion pair reagents used in reversed-phase LC and the effect on ionisation? I have read many papers in the area of peptide and protein analysis by LC/MS and most report the use of TFA in their solvents. Any ideas on this would be greatly appreciated. Robin J. Philp Institute of Molecular and Cell Biology Singapore. ****************************************************************************** From: jbeale@reed.edu (Jay Beale) Subject: Is there a digest yet? Date: 13 Jun 1995 15:49:22 GMT Organization: Reed College, Portland, Oregon Has the sci.techniques.mass-spec mailing list digest begun yet? -- -Jay Beale jbeale@reed.edu jbeale@epitope.com (not private, limited access) ****************************************************************************** From: jbeale@reed.edu (Jay Beale) Subject: ?: HP5971 data quality control Date: 13 Jun 1995 22:04:06 GMT Organization: Reed College, Portland, Oregon This is a question relating to quality control for data aquired using a Hewlett-Packard 5971 mass spec. Some background: we are trying to develop some SIM methods for validating results from ELISA optimization experiments. Our method for the development of the chromatographic methods is to analyze a set of standards, then make some change(s) in data acquisition or sample prep, run the set of standards under the new conditions, then compare the results from the two sets of standards. The weakness in this method is that it assumes that the mass spec is responding the same during each run. Unfortunately for us, some of our samples cause the source to get dirty in a week or less, depending on the usage and therefore we can't assume that we get the same response from week to week. We can use the tuning parameters and tune results to track some of the performance characteristics of the machine, such as mass resolution, but getting a handle on signal-to-noise ratios has been more difficult. I have been contemplating running an external control, of our analytes or other compounds producing the same ions, and tracking the machine's response from week to week. I am wondering if the signal-to-noise ratio can be determined from a single run in this way, i.e. is noise = baseline and signal = absolute peak height for each ion?. It is obvious that integration of the peaks in SIM mode does not give s-n information, since the noise is subtracted when the data system draws the baseline under the peak. Does anyone know whether it is possible to force the data system (HP MSChemstation for Windows) to integrate the absolute peak area, i.e. draw vertical lines from the peak start and stop down to zero abundance and sum the area of the peak starting from "absolute" zero? Thanks for any input Jay Beale jbeale@reed.edu jbeale@epitope.com -- -Jay Beale jbeale@reed.edu jbeale@epitope.com (not private, limited access) ****************************************************************************** From: Heinrich Luftmann Subject: TOF HV-switch Date: 14 Jun 1995 11:15:26 GMT Organization: Organisch Chemisches Institut d. Universitdt -- Heinrich L. Muenster -Germany I am looking for an electronic circuit whitch is capabel to switch 2 KV within some ns on a DC-level of about 20 KV. I want to use it in a TOF-MS for delayed extraction. Heinrich ****************************************************************************** From: jbeale@reed.edu (Jay Beale) Subject: HP 5971 for quantitation; quality control question Date: 13 Jun 1995 16:20:31 GMT Organization: Reed College, Portland, Oregon I've got some questions about setting up some sort of quality control program for our Hewlett-Packard 5971 mass spec. We've been using it to develop methods for quantitation of drugs of abuse and are freqently performing analyses down near the limit of quantitation. Our method development process is based on preparing a set of standards, analyzing them, then making changes in sample prep or data acquisition parameters and then running another set of standards under the new conditions. We then compare the results of the two sets of standards to decide whether the changes produced better results. This assumes that the mass spec was in the same condition during the two runs, in particular as far as signal to noise ratio. Lately we've had to run some samples which dirty the source over the timespan of one week or less, so we can no longer assume that the machine is performing the same from one run of standards to the next. I've been trying to come up with a routine which we can perform which will give us some kind of quantitative insight into the machine's condition. We had been obtaining qualitative data by looking at the lens ramps, particularly the repeller ramp, but this is too subjective an indication of the source condition for our needs. I've been contemplating making up an external standard, possibly of PFTBA in some solvent, and running that. I'd like to be able to extract signal-to-noise information from the external standard, and have been wondering if baseline=noise and peak height (absolute, not height above the baseline) is = to signal. Does this make sense? For our purposes, signal-to-noise is really the only thing we need to keep an eye on that is not already kept track of through our tuning process. Thanks, Jay Beale jbeale@reed.edu jbeale@epitope.com -- -Jay Beale jbeale@reed.edu jbeale@epitope.com (not private, limited access) ****************************************************************************** From: jbeale@reed.edu (Jay Beale) Subject: mailing list digest? Date: 13 Jun 1995 22:05:43 GMT Organization: Reed College, Portland, Oregon Is there a mailing list digest for this newsgroup? Jay Beale jbeale@reed.edu jbeale@epitope.com -- -Jay Beale jbeale@reed.edu jbeale@epitope.com (not private, limited access) ****************************************************************************** From: "John Bartmess" Organization: Univ. of Tenn. Dept. of Chemistry Date: Wed, 14 Jun 1995 17:06:59 EST Subject: A mailing list for STM-S Priority: normal This is information for readers of sci.techniques.mass-spec (STM-S) to pass along to those who cannot read Netnews, for whatever reason, but do have access to e-mail. There is a mailing list being set up, that will remail the contents of STM-S to anyone who wishes to subscribe. This mailing list is maintained at the Chemistry Dept., University of Tennessee, Knoxville by John Bartmess . This list is "public," which means that anyone may subscribe. It is also a one-way system, in that anything that subscribers want posted to STM-S should be sent to the moderator of that group, at . Other than a subscription request, anything sent to this mailing list at , will go into the bit bucket. Likewise, any requests to subscribe sent directly to me, , will not be acted on. I welcome personal e-mail *about* mass spec topics. {Ion Thermochemistry To Go!} The contents of the newsgroup will be mailed to subscribers as an ascii file once to twice a week, depending on the posting level of the newsgroup. Subscribers thus will not get each post on the group separately, but many of them concatenated into one file. To subscribe to this listserver, send a message to with 1. *no subject*, and 2. the *only* text being: SUB STMSLIST To unsubscribe, similarly send a message with the only text being: UNSUB STMSLIST Comments regarding STM-S should be sent to the Moderator of that group, Dave Bostwick if you wish to keep them private, or to the Newsgroup itself , if you wish to make them public. John --=--=--=--=--=--=--=--=--=--=--=--=--=--=--=--=--=-=--=--=--=--=--=--=- | John Bartmess | Organic Chem! || my opinions, being antithetical | | Department of Chemistry || to "big time" football, cannot | | University of Tennessee || be those of the Univ. of Tennessee| | Knoxville TN 37996-1600 || "Anions are more fun!" | | (615) 974-6578 Fax: 974-3454 || | --=--=--=--=--=--=--=--=--=--=--=--=--=--=--=--=-=--=--=--=--=--=--=--=- ****************************************************************************** From: topaz56@cyberg8t.com (BlueShift) Subject: MALDI Date: Wed, 14 Jun 1995 22:21:55 Organization: Cyberg8t Anyone have some good MALDI stories? ****************************************************************************** ****************************************************************************** From: pmayer@email.unc.edu (Paul Mayer) Subject: this years ASMS meeting Date: 15 Jun 1995 20:05:32 GMT Organization: The University of North Carolina at Chapel Hill Hello. I was interested in hearing people's comments on this year's ASMS meeting. I was unable to attend this year and was curious to know how things went. Any specific comments on fundamental vs analytic/biochem content are particularly welcome. Thanks Paul Mayer ****************************************************************************** From: mcope@ix.netcom.com (Michael Cope) Subject: Portable Gas Chromatograph Mass Spectrometer Date: 14 Jun 1995 15:49:41 GMT Organization: Netcom NNTP-Posting-Host: ix-dfw10-28.ix.netcom.com Can anyone give me advice via email? I am involved in the selection process for purchasing a GCMS which will be used for Environmental and Materials sample analysis. It needs to be portable and have high resolution. Currently we are looking at a Viking Instruments model which is portable (if you are a gorilla), but I want to insure that we are considering our alternatives. This is for the Dallas Environmental Health Center. Does anyone have equipment advice? What other newsgroups should I ask? What internet resources should I tap into to research this topic? ****************************************************************************** From: pmayer@email.unc.edu (Paul Mayer) Subject: this years ASMS meeting Date: 15 Jun 1995 20:05:32 GMT Organization: The University of North Carolina at Chapel Hill Hello. I was interested in hearing people's comments on this year's ASMS meeting. I was unable to attend this year and was curious to know how things went. Any specific comments on fundamental vs analytic/biochem content are particularly welcome. Thanks Paul Mayer ****************************************************************************** From: "Kermit K. Murray" Subject: WWW Site for Mass Spectrometry Date: 15 Jun 1995 23:02:37 GMT Organization: Emory University Chemistry I have a WWW site for mass spectrometry at http://tswww.cc.emory.edu/~kmurray/mslist.html It is searchable and has links to other MS web sites and resources. If you have an MS site, send me the URL and I'll put it in the list. Kermit K. Murray kmurray@emory.edu http://tswww.cc.emory.edu/~kmurray/ ****************************************************************************** From: depauw@gw.unipc.ulg.ac.be (De Pauw Edwin) Subject: Electrospray for the monitoring of photochemical reactions Date: Mon, 19 Jun 1995 18:50:51 +0200 Organization: Liege University ON LINE STUDY OF PHOTOCHEMICAL REACTIONS BY ELECTROSPRAY MASS SPECTROMETRY Electrospray mass spectrometry is a very interesting tool for the study of photochemical reactions in solution. The evolution of the nature and the concentration of reactants, long lifetime intermediates and final compounds can be unambiguously monitored. Two types of reactors directly linked to the electrospray source of a quadrupole mass spectrometer have been constructed and evaluated: a non stirred flow type reactor and a static, stirred reactor. The photosubstitution of chlorine in chlorpromazine has been choosen as a test reaction. The reaction has been monitored in water/acetonitrile and in methanol solutions. The quenching effect of oxygen has been measured by comparing kinetics in oxygen saturated and outgassed solutions. From experiments in the static reactor, rate constants have been obtained. From the rate constants, the behaviour of the flow reactor has been modelled. Parameters such as the flow, the lenght of the reactor can be easily controlled to obtain stationnary states for specific compounds of different lifetimes.The flow reactor has then been used to follow the addition reaction of methoxypsoralene with thymine and oligonucleotides. The direct monitoring of photochemical reactions by Electrospray mass spectrometry appears to be an excellent tool for the quantification of drugs photoactivity and to study their reaction mechanisms, particularly their addition on bioploymers. We currently use it also for the estimation of reaction yields in the destruction of toxic compounds in solution (chlorinated phenols). It can also be used as a post column reactor for specific labelling in HPLC detection by mass spectrometry. ****************************************************************************** From: "kasi V. Somayajula" Subject: Long due Date: 16 Jun 1995 19:25:32 GMT Organization: University of Pittsburgh Welcome to the mass spec news group. I thank all the folks at Georgia Tech for the efforts in bringing this news group. Let us do some PEEKING. Kasi -- David E. Bostwick Georgia Institute of Technology, Atlanta, GA, 30332 david.bostwick@chemistry.gatech.edu ****************************************************************************** ****************************************************************************** From: gmt1810@trex.oscs.montana.edu (Mark Tarka) Subject: Re: Electrospray for the monitoring of photochemical reactions Date: Mon, 19 Jun 1995 22:45:35 Organization: Montana State University In article <3s4ark$1fm@acmex.gatech.edu>, depauw@gw.unipc.ulg.ac.be (De Pauw Edwin) writes: >ON LINE STUDY OF PHOTOCHEMICAL REACTIONS BY ELECTROSPRAY MASS SPECTROMETRY [Snip...] >static, stirred reactor. The photosubstitution of chlorine in >chlorpromazine has been choosen as a test reaction. The reaction has been [Snip...] >then been used to follow the addition reaction of methoxypsoralene with >thymine and oligonucleotides. > The direct monitoring of photochemical reactions by Electrospray mass >spectrometry appears to be an excellent tool for the quantification of >drugs photoactivity and to study their reaction mechanisms, particularly >their addition on bioploymers. We currently use it also for the estimation Err, I'm guessing here, but I was under the impression that pharmaceuticals, injested, never saw the light of day. What is the driving force behind this research (who funded it)? >of reaction yields in the destruction of toxic compounds in solution Now that's interesting. >(chlorinated phenols). It can also be used as a post column reactor for >specific labelling in HPLC detection by mass spectrometry. Specific labelling...what? Feed an HPLC into an ESMS, sure. Mark (Oops...there goes my future.....:) Mark gmt1810@msu.oscs.montana.edu ****************************************************************************** From: gmt1810@trex.oscs.montana.edu (Mark Tarka) Subject: Re: no subject (file transmission) Date: Mon, 19 Jun 1995 22:54:50 Organization: Montana State University In article <3s3rat$h8i@acmex.gatech.edu>, db32@prism.gatech.edu (David E. Bostwick) writes: [Snip...] >article to improve its readability. When posting, please be sure your >subject header is correct, and that your lines fit on a standard 80-column >terminal. Gee, I hope I don't generate a lot of static about this, but wouldn't it be a good idea to limit one's line length to 70 charaters or less, so quotations would be readable. Folks could set that limit for their editors (that is, the software that allows them to write messages), using some sort of "set" command (e.g. in VMS, "set right margin 70"). Mark Mark gmt1810@msu.oscs.montana.edu ****************************************************************************** From: jbeale@reed.edu (Jay Beale) Subject: Digest functioning? Date: 20 Jun 1995 21:05:20 GMT Organization: Reed College, Portland, Oregon Hi all, glad to see this thing is finally up and running. Does anyone know whether the mailing list digest for this newsgroup is functioning? Some colleagues have e-mail only and would like to follow the discussions... -Jay Beale jbeale@reed.edu jbeale@epitope.com -- -Jay Beale jbeale@reed.edu jbeale@epitope.com (not private, limited access) ****************************************************************************** From: "Terry L. Kaduce" Subject: On Line Databases Date: Tue, 20 Jun 1995 16:49:33 -0500 Organization: University of Iowa, Iowa City, IA, USA Is there an on line database which I can use to compare my aquired spectra with authentic standards? I working with fatty acid methyl esters and arachidonic acid metabolites. Thank you Terry L. Kaduce University of Iowa Dept of Biochemistry 4-555 BSB Iowa City, IA 52242 319/335-7914 ****************************************************************************** From: "Rob O'Brien" Subject: Negative Chemical Ionization - Discussion/Reference text Date: 21 Jun 1995 01:16:18 GMT Organization: National Research Council, Canada I have recently posted this message in sci.chem.analytical. One reader pointed out that this would also be an appropriate place to post. ++++++++++++++++++++++++++++++++++++ This information text is being set up as a test project to evaluate the feasibility of developing an online "living" reference source. Ideally, information contained within this document will be continuously challenged, reworked, and rethought to produce a valuable up-to-date reference manual. Although, this project seems, at least to me, to be worthwhile as a general project, in order for me to be able to spend time developing this I am focusing this text on my present research topic Negative Chemical Ionization / Mass Spectroscopy. ====================================================== Preamble : The following is a proposed table of contents for the NCI/MS discussion/reference text. As a first step this table of contents is being posted and readers will be asked to comment on it's format, produce short monograph's, or suggest available electronic information sources on any or all of the subtopics listed. Information can be forwarded to me or posted to the sci.chem.analytical newsgroup. I would suggest that if submissions are posted to the newsgroup that the subject line contain NCI-D/RT to indicate to other readers that is related to this topic. Furthermore, an indication of which section is being discussed such as 2A.1 for Electron Affinity would be of assistance. Submissions and comments will be posted along with my own contributions near the end of July, 1995. Rob O'Brien PHD Candidate, Carleton University ======================== Negative Chemical Ionization / Mass Spectroscopy Table of Contents 1 Introduction and scope 2. Fundamentals 2A Thermodynamics 2A.1 Electron affinity 2B Kinetics 2C Reaction Mechanisms 3. Instrumentation 3A Ion Source requirements 3A.1 Measurement issues 3A.1A Pressure 3A.1B Temperature 3A.1C Electron density 3A.1D Ventilation rate 3B Instrument comparisons 3C Calibration methods 3D Sample introduction 3E Reagent systems 3E.1 Methane 3E.2 Ammonia 3E.3 Mixed gas systems 4. Analytical Applications 4A Detection limit improvement 4B Molecular weight determination 4C Structure determination 4D Isomer discrimination 5. Reviewed References 5A Journal Articles 5B Books 5C Electronic Information Appendix I - Frequently encountered problems and solutions Appendix II - Spectra data base ****************************************************************************** From: ihogben@tartarus.uwa.edu.au (Ian Hewlett Hogben) Subject: Lamer Question: AMS and Archaeology Date: 21 Jun 1995 03:39:15 GMT Organization: The University of Western Australia I apologise for the lamer question in what seems to be a largely academic environment, but I am an archaeology student, and all texts I read for my qustion go _way_ over my head. I have been vexed by the problem of dating archaeological samples that predate 40 000 years; the old method of radiocarbon dating would not be reliable with samples older, as there was too little 14c to date reiably. With the advent of AMS dating, I would have thought that this date could be pushed back to, say, 60 000 years bp or earlier. If it can, is this only theoretical? If so, why? Thank you fer yer patience. Aias. =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- |"A poem: a story in meter or rhyme." | |'Ahh. `There once was a man from Nantucket...`' | |"You've been talking to Garibaldi again, haven't you?" | | -- Delenn and Sinclair, "The Gathering" Babylon5 | =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- | Aias. =-aka-= ihogben@tartarus.uwa.edu.au | =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- ****************************************************************************** From: depauw@gw.unipc.ulg.ac.be (De Pauw Edwin) Subject: www home page for mass spectrometry at liege university Date: Wed, 21 Jun 1995 09:19:36 +0200 Organization: Liege University I have a WWW site for mass spectrometry at http://www.pne.ulg.ac.be/mslab/mslab.html We start a collection of hints and tricks to help new (and others) users of mass spectrometry to better use and understand this fascinating method. send me yours and I'll put them in the records. De Pauw Edwin depauw@gw.unipc.ulg.ac.be -- De Pauw Edwin Mass Spectrometry Laboratory, B6 Chemistry Institute, Liege University B4000-Liege Belgium depauw@gw.unipc.ulg.ac.be ****************************************************************************** From: Heinrich Luftmann Subject: High Voltage Switch Date: 21 Jun 1995 08:23:35 GMT Organization: Organisch Chemisches Institut d. Universitdt I am looking for an electronic device whitch is capabel to switch 2kV DC on a level of 20kV above ground. This must be done within some ns but the current load is very small. I need such a device for my TOF mass spectrometer to improve the resolution by delayed extraction of the laser produced ions. An electronic circuit or a commerical source would be helpful. luftman@uni-muenster.de (Heinrich Luftmann) ****************************************************************************** From: kore@cityscape.co.uk (Steve Mullock) Subject: Re: TOF HV-switch Date: Wed, 21 Jun 1995 08:05:42 GMT Organization: CityScape Internet Sevices Heinrich Luftmann wrote: >...looking for... electronic circuit whitch is capabel to switch 2 KV >within some ns on a DC-level of about 20 KV. I want to use it in a TOF-MS >for delayed extraction. A company called Behlke offer a range of high voltage switch modules which consist of stacks of CMOS switches. These can switch several kV in about 5ns (If you're very careful with the rest of the layout) and can be flaoted. The standard units float to 10kV but there are some that go up to 30kV, best to talk details with them: Behlke Electronic GmbH tel: 069 733215 fax: 069 733179 By the way, we as a company have designed and built a variety of TOF mass spectrometers and have a number of spectrometer modules that we are happy to offer to those designing their own. For example, we have developed a relatively inexpensive ion counting/timing electronics unit that requires only an ordinary modestly endowed PC and a detector to create time of flight spectra at high data rates (dead time 2ns, sustained histogramming rate 5MHz). We are also happy to offer design consultancy services on TOF MS or other UHV related problems. If you, or any one else out there, would like further details or to receive copies of our newsletter please get in touch. Steve Dr S.J. Mullock, Kore Technology Ltd. 291, Cambridge Science Park Milton Road Cambridge CB4 4WF Tel: 44 (0) 1223 420840 Fax: 44 (0) 1223 426 041 ****************************************************************************** From: "Kermit K. Murray" Subject: Re: TOF HV-switch Date: 21 Jun 1995 14:24:10 GMT Organization: Emory University Chemistry Heinrich Luftmann wrote: >I am looking for an electronic circuit whitch is capabel to switch 2 KV >within some ns on a DC-level of about 20 KV. I want to use it in a TOF-MS >for delayed extraction. There's a company in Ft. Collins, Colorado that sells high voltage switches and pulsed power supplies: Directed Energy, Inc. 2301 Research Blvd. Suite 101 Ft. Collind, CO 80526 Ph. 303-493-1901 Fax. 303-493-1903 I have one of their pulsers that will switch +/- 3kV with < 45 ns rise and fall to > 10 kHz rep rate. It's not floatable, but you could put it in a plexiglass box on an isolation transformer and trigger it with an optical isolator. I am thinking of doing this myself, so if anyone knows where I can get an isolation transformer that can hold off 20 to 30 kV, please let me know. Kermit Kermit K. Murray kmurray@emory.edu http://tswww.cc.emory.edu/~kmurray/ ****************************************************************************** From: "Kermit K. Murray" Subject: Re: mailing list digest? Date: 21 Jun 1995 14:51:07 GMT Organization: Emory University Chemistry jbeale@reed.edu (Jay Beale) wrote: > >Is there a mailing list digest for this newsgroup? > >Jay Beale >jbeale@reed.edu >jbeale@epitope.com (not private, limited access) > >[I'm not sure if John is going to keep copies of the mail he sends out >from his listserver, but we will save old postings in a file here. It >won't be an archive as such, and the old postings won't be around forever, >but if you need info from a recent previous post, we (or John, if he has it) >should be able to find it for you. - db] I have been archiving the listserver posts for the the discussion group and STMS in a searchable database available on WWW. The URL is reachable from the MS page I have at http://tswww.cc.emory.edu/~kmurray/mslist.html (the one I plugged in an earlier post). The search engine is a nice add-on to MacHTTP and it is running on one of my lab Macintosh computers. I'll keep on archiving server posts as much as time an disk space permits. Kermit Kermit K. Murray kmurray@emory.edu http://tswww.cc.emory.edu/~kmurray/ ****************************************************************************** From: "John Bartmess" Organization: Univ. of Tenn. Dept. of Chemistry Date: Wed, 21 Jun 1995 11:11:54 EST Subject: Re: Negative Chemical Ionization - Discussion/Reference text Priority: normal Rob O'Brien wrote, concerning topics for a text or discussion on NCI: >2. Fundamentals > 2A Thermodynamics > 2A.1 Electron affinity Just to make you aware, there is a comprehensive and evaluated data base of all electron affinities (and gas phase acidities and heats of formation of negative ions and cluster thermochemistry...) in the literature, put out as a data base by the US National Institute of Standards and Technology, as Standard Reference Data Base 19B (19A, bundled with it, contains all positive ion thermochemistry). This is an ongoing project, with approximately biannual updates. Contact Joan Sauerwein at NIST for ordering information. It is PC based, but can be made to run on a Mac. --=--=--=--=--=--=--=--=--=--=--=--=--=--=--=--=--=-=--=--=--=--=--=--=- | John Bartmess | Organic Chem! || my opinions, being antithetical | | Department of Chemistry || to "big time" football, cannot | | University of Tennessee || be those of the Univ. of Tennessee| | Knoxville TN 37996-1600 || "Anions are more fun!" | | (615) 974-6578 Fax: 974-3454 || | --=--=--=--=--=--=--=--=--=--=--=--=--=--=--=--=-=--=--=--=--=--=--=--=- ****************************************************************************** From: dpvw@iastate.edu (Dave P VanderWiel) Subject: Anyone using SSITKA techniques? Date: 21 Jun 1995 19:33:43 GMT Organization: Iowa State University, Ames, Iowa USA Originator: dpvw@eng3.iastate.edu If there's anyone out there using steady-state isotopic transient analysis (SSITKA) methods for studying catalysis and if they don't mind me bugging them occasionally - let me know! I'm building a SSITKA apparatus for studying Fischer-Tropsch synthesis, and I could really use some help. Thanks! Dave VanderWiel Dept. Chemical Engineering Iowa State University ****************************************************************************** From: schiller@prl.philips.nl (schiller c) Subject: Can mass spect. resolve different bond types? Organization: Philips Research Laboratories Eindhoven, Netherlands Date: Thu, 22 Jun 1995 08:47:08 GMT Does mass spectroscopy have the resolving power to measure mass differences between compounds with the same chemical formula but with different structure? This requires a resolution of the order of 10^-10; such resolution would allow to measure bond energies directly, by measuring the chemical mass defect. More simply, measuring the masses of H2, O2 (or better, H and 0) and H20, one could determine their binding energy. Is such a resolution attainable with state of the art systems? Thanks Christoph Schiller Electronic mail address : schiller@prl.philips.nl Postal address : Christoph Schiller, Philips Research Laboratories, Building WY 41, Prof. Holstlaan 4, 5656AA Eindhoven, The Netherlands tel +31-40-743360 or +31-40-743235, fax +31-40-743478 -- ****************************************************************************** From: jesnow@geobar.mpch-mainz.mpg.de (Jonathan E. Snow) Subject: Hello, mass spectrometric world. Date: Thu, 22 Jun 1995 11:08:27 GMT Organization: Max-Planck Institut fuer Chemie I'm very happy the CFV went through and I'm grateful to whoever had the initiative to put it through. As an isotope geochemist, mass spectometry is the major tool I use in my work on the radiogenic isotopes of Pb, Sr, Nd and Os. Mostly, the technology of solid source mass spectrometers has been stable for about the past 40 years, since the late AO Nier invented the magnetic sector analyzer. Recently, there have been some new developments which may change all that, and I hope to discuss that a little in this space. I'm now going to sit down and email as many people as I can think of about the existence of this group. Cheers, jon. ---------------------------------------------------- Jonathan E. Snow Max-Planck Institut fuer Chemie, Abt. Geochemie Postfach 3060, D-55020 Mainz, Germany jesnow@geobar.mpch-mainz.mpg.de TEL:(01149) 6131 305 202 (or 281 to lv. msg.) FAX:(01149) 6131 371 051 ---------------------------------------------------- ****************************************************************************** From: kore@cityscape.co.uk (Steve Mullock) Subject: Re: Portable Gas Chromatograph Mass Spectrometer Date: Thu, 22 Jun 1995 10:40:02 GMT Organization: CityScape Internet Sevices mcope@ix.netcom.com (Michael Cope) wrote: >I am involved in the selection process for purchasing a GCMS which will >be used for Environmental and Materials sample analysis. It needs to >be portable and have high resolution. Currently we are looking at a >Viking Instruments model which is portable (if you are a gorilla), but >I want to insure that we are considering our alternatives. This is for >the Dallas Environmental Health Center. Dear Michael I saw on the mass spec newsgroup that you were in the process of selecting a portable GCMS. You may not be aware that we are developing portable time-of-flight mass spectrometers here at Kore. We will have prototypes ready for field trials around late August this year. These will not have GC interfaces fitted however as they fit into suitcases suitable for in cabin flight storage you do not need gorilla-like strength to carry them.If you would like more information or even perhaps to participate in these trials can you give us your telephone number and postal address so that we can contact you. Barrie Griffiths tel +44 1223 420840 Kore Technology Ltd, Cambridge Science Park, Cambridge CB4 4WF,UK. -- Dr S.J. Mullock Kore Technology Ltd. 291, Cambridge Science Park Milton Road Cambridge CB4 4WF UK Tel: 44 (0) 1223 420840 Fax: 44 (0) 1223 426041 ****************************************************************************** From: "Margaret P. Ricci" Subject: WWW page for isotope ratio monitoring-GCMS Date: 22 Jun 1995 14:53:29 GMT Organization: Indiana University, Bloomington I'm sure glad someone started up this newsgroup - it has saved me a lot of trouble. Thanks. There is a home page for isotope ratio monitoring-gas chromatography mass spectrometry. This technique is branching out in a thousand directions at the moment. The home page includes a description of the technique as applied specifically to CO2 as well as an EXTENSIVE bibliography which will give the surfer a good idea of what the technique is being used for and where it is going. There is also a lot of specific information for users of the technique - software updates, documentation and so on. Here's the URL: http://silver.ucs.indiana.edu/~isotopes/home.html Drop by for a visit. Margaret P. Ricci isotopes@indiana.edu ****************************************************************************** From: pggreen@cco.caltech.edu (Peter G. Green) Subject: ICP-MS Analyses Service? Followup-To: sci.techniques.mass-spec Date: Thu, 22 Jun 95 15:26:57 GMT Organization: Caltech (Environmental Engineering Science) Howdy, I'm looking for recommendations of commercial services that will do ICP-MS analyses. US and/or Canada preferred. Needing pbb and ppt performance. Email and/or post. Thanks in advance, -Peter Green ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Peter G. Green, Ph. D. Senior Scientist Keck 201 <= on foot (818) 395-3787 Caltech 138-78 <= mail/UPS fax: -3170 Pasadena, CA 91125 USA or -2940 pggreen@cco.caltech.edu Environmental Eng. Sci. ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ****************************************************************************** Date: Tue, 20 Jun 95 16:40:56 0400 From: "Kermit K. Murray" Organization: Emory University Chemistry Subject: Re: Can the chemical mass defect be measured by weighing ? I'm forwarding this to sci.techniques.mass-spec. Cross-post replies to sci.chem and sci.physics. Joel Polowin wrote: >vanesch@dice2.desy.de (Patrick P. E. Esch) wrote: > >> Howdy ! Sorry, but the "energy released in a chemical reaction" >> has a mass defect just as well as the nuclear variety. >> Meaning: YES, H2O is a little bit lighter than 1/2(2 H2 + 02). >> And the difference in weight would be dm = dE / c2 with dE the >> amount of energy released by burning H2. >> Only, as the masses of the atoms are of the order of 1GeV >> and the energy of the order of a few eV, this would be a >> 10-9 effect, and I don't think it is possible to weight something >> with an accuracy of 10 digits. > >I have been told that some mass-spectroscopy group is able to measure >a mass difference between, say, a structure with a double bond and >the same atoms arranged in a cyclic structure, because of the >difference in bond energies. I remain profoundly skeptical, for >reasons similar to your calculation above. > >Then again, Mossbauer spectroscopy works by doppler-shifting gamma >radiation (3E8 m/s) by amounts on the order of a few cm per second >(~3E-2 m/s). I won't simply dismiss these claims out of hand. > >Joel >polowin@hyper.com >http://www.hyper.com > Kermit K. Murray kmurray@emory.edu http://tswww.cc.emory.edu/~kmurray/ ****************************************************************************** Date: Tue, 20 Jun 95 16:40:56 0400 From: "Kermit K. Murray" Organization: Emory University Chemistry Subject: Re: Can the chemical mass defect be measured by weighing ? I'm forwarding this to sci.techniques.mass-spec. Cross-post replies to sci.chem and sci.physics. Joel Polowin wrote: >vanesch@dice2.desy.de (Patrick P. E. Esch) wrote: > >> Howdy ! Sorry, but the "energy released in a chemical reaction" >> has a mass defect just as well as the nuclear variety. >> Meaning: YES, H2O is a little bit lighter than 1/2(2 H2 + 02). >> And the difference in weight would be dm = dE / c2 with dE the >> amount of energy released by burning H2. >> Only, as the masses of the atoms are of the order of 1GeV >> and the energy of the order of a few eV, this would be a >> 10-9 effect, and I don't think it is possible to weight something >> with an accuracy of 10 digits. > >I have been told that some mass-spectroscopy group is able to measure >a mass difference between, say, a structure with a double bond and >the same atoms arranged in a cyclic structure, because of the >difference in bond energies. I remain profoundly skeptical, for >reasons similar to your calculation above. > >Then again, Mossbauer spectroscopy works by doppler-shifting gamma >radiation (3E8 m/s) by amounts on the order of a few cm per second >(~3E-2 m/s). I won't simply dismiss these claims out of hand. > >Joel >polowin@hyper.com >http://www.hyper.com > Kermit K. Murray kmurray@emory.edu http://tswww.cc.emory.edu/~kmurray/ ****************************************************************************** Date: Tue, 20 Jun 1995 17:42:35 +0200 From: depauw@gw.unipc.ulg.ac.be (Edwin De Pauw) Subject: Re: Electrospray for the monitoring of photochemical reactions In article (Dans l'article) <3s6f6e$1nu@acmex.gatech.edu>, gmt1810@trex.oscs.montana.edu (Mark Tarka) wrote (=E9crivait) : > In article <3s4ark$1fm@acmex.gatech.edu>, depauw@gw.unipc.ulg.ac.be (De Pa= uw >Edwin) writes: > >ON LINE STUDY OF PHOTOCHEMICAL REACTIONS BY ELECTROSPRAY MASS SPECTROMETR= Y > > [Snip...] > >static, stirred reactor. The photosubstitution of chlorine in > >chlorpromazine has been choosen as a test reaction. The reaction has been > [Snip...] > >then been used to follow the addition reaction of methoxypsoralene with > >thymine and oligonucleotides. > > > The direct monitoring of photochemical reactions by Electrospray mass > >spectrometry appears to be an excellent tool for the quantification of > >drugs photoactivity and to study their reaction mechanisms, particularly > >their addition on bioploymers. We currently use it also for the estimatio= n > > Err, I'm guessing here, but I was under the impression that > pharmaceuticals, injested, never saw the light of day. What is the > driving force behind this research (who funded it)? > > >of reaction yields in the destruction of toxic compounds in solution > > Now that's interesting. > > >(chlorinated phenols). It can also be used as a post column reactor for > >specific labelling in HPLC detection by mass spectrometry. > > Specific labelling...what? Feed an HPLC into an ESMS, sure. > > > Mark (Oops...there goes my future.....:) > > Mark gmt1810@msu.oscs.montana.edu Chlorpromazine has a secondary effect in opacifying the cornea where I suppose light is going to. Other similar compounds are used as phototherapeutic drugs (skin treatment). Ingestion is surely not the only way to administrate drugs. Post column derivatization is often used to increase detection sensitivity and selectivity. The postcolumn photoaddition can be used to selectively label the photoreactive compound before its entrance into the ion source. Coupled with a MS/MS scan, it allows the specific detection of the target compound or its quantification by MRM (multiple reaction monitoring) De Pauw Edwin Laboratoire de Spectrom=E9trie de Masse Universit=E9 de Liege B4000-Liege Belgium Tel 00.32.41.663435 FAX 00.32.41.663413 email depauw@gw.unipc.ulg.ac.be www:http://www.pne.ulg.ac.be/mslab/mslab.html ****************************************************************************** Date: Tue, 20 Jun 95 16:40:56 0400 From: "Kermit K. Murray" Organization: Emory University Chemistry Subject: Re: Can the chemical mass defect be measured by weighing ? I'm forwarding this to sci.techniques.mass-spec. Cross-post replies to sci.chem and sci.physics. Joel Polowin wrote: >vanesch@dice2.desy.de (Patrick P. E. Esch) wrote: > >> Howdy ! Sorry, but the "energy released in a chemical reaction" >> has a mass defect just as well as the nuclear variety. >> Meaning: YES, H2O is a little bit lighter than 1/2(2 H2 + 02). >> And the difference in weight would be dm = dE / c2 with dE the >> amount of energy released by burning H2. >> Only, as the masses of the atoms are of the order of 1GeV >> and the energy of the order of a few eV, this would be a >> 10-9 effect, and I don't think it is possible to weight something >> with an accuracy of 10 digits. > >I have been told that some mass-spectroscopy group is able to measure >a mass difference between, say, a structure with a double bond and >the same atoms arranged in a cyclic structure, because of the >difference in bond energies. I remain profoundly skeptical, for >reasons similar to your calculation above. > >Then again, Mossbauer spectroscopy works by doppler-shifting gamma >radiation (3E8 m/s) by amounts on the order of a few cm per second >(~3E-2 m/s). I won't simply dismiss these claims out of hand. > >Joel >polowin@hyper.com >http://www.hyper.com > Kermit K. Murray kmurray@emory.edu http://tswww.cc.emory.edu/~kmurray/ ****************************************************************************** Date: Thu, 22 Jun 1995 23:31:15 +0000 (GMT) From: ddxdd@IMAP1.ASU.EDU Subject: Re: TOF HV-switch Organization: daves not here Heinrich Luftmann (luftman@uni-muenster.de) wrote: : -- : Heinrich L. : Muenster -Germany : I am looking for an electronic circuit whitch is capabel to switch 2 KV : within some ns on a DC-level of about 20 KV. I want to use it in a TOF-MS : for delayed extraction. : Heinrich try contacting Behlke Electonic GmbH, Postisch 190249, D-60069, Frankfurt, phone 069733218. they make what you are looking for, but it does come at a hefty price. we have found that their switches also seem to be fragile with respect to damage caused by discharges. -d^2 ****************************************************************************** From: rjnemery@uniwa.uwa.edu.au (Neil Emery) Subject: MS for ureides? Date: 23 Jun 1995 07:47:49 GMT Organization: The University of Western Australia We are botanists, using a HP 5970 MSD in series with a HP 5890 GC. So far we have analyzed most amino acids, and we are now interested in analyzing the ureides (allantoin, allantoic acid, etc). Has anyone out there ever analyzed these compounds, and thus would be able to advise us on expected spectra, of any sort of derivatized ureides? We've noticed that some medical labs have done so, but in the methods of published works, the details of the mass spec work are not mentioned. Grateful for any response. Sincerely Neil Emery ****************************************************************************** From: pzadoroz@wimsey.com (Peter Zadorozny) Subject: Re: ICP-MS Analyses Service? Date: Fri, 23 Jun 1995 07:55:43 -0800 Organization: GVRD In article <3sc6ip$t0r@acmex.gatech.edu>, pggreen@cco.caltech.edu (Peter G. Green) wrote: > Howdy, > > I'm looking for recommendations of commercial services that will do > ICP-MS analyses. US and/or Canada preferred. Needing pbb and ppt > performance. Try Elemental Research Inc 309-267 West Esplanade North Vancouver B.C. Canada Phone (604) 986-0445 Fax (604) 986-0071 I know they have been around for year doing ICP-MS , never used them but have been through their lab, very nice set up. I think they have a good reputation. Peter ****************************************************************************** From: Kevin.R.Boyce@gsfc.nasa.gov (Kevin R. Boyce) Subject: Re: Can mass spect. resolve different bond types? Date: Fri, 23 Jun 1995 13:19:47 -0400 Organization: NASA Goddard Space Flight Center -- Greenbelt, Maryland USA In article <3sbpml$d5t@acmex.gatech.edu>, schiller@prl.philips.nl (schiller c) wrote: >Does mass spectroscopy have the resolving power to measure mass >differences between compounds with the same chemical formula but with >different structure? > >This requires a resolution of the order of 10^-10; such resolution would >allow to measure bond energies directly, by measuring the chemical mass >defect. > >Is such a resolution attainable with state of the art systems? Well, 10^-10 is achievable with Single-Ion Cyclotron Resonance. See, for example, the latest paper from the MIT ICR gang: DiFilippo et al, _Accurate Atomic Masses for Fundamental Metrology_, PRL, vol 73, pp. 1481-1484 (1994) But you need to do better than that to measure bond energies with any accuracy. Rest assured that the ICR folks are working toward just that goal. It's not exactly off-the-shelf equipment, though... :-) -- Kevin Kevin.R.Boyce@gsfc.nasa.gov "Well I'm not really familiar with that study." --Paul Brodeur ****************************************************************************** From: jbeale@reed.edu (Jay Beale) Subject: Re: mailing list digest? Date: 23 Jun 1995 17:35:43 GMT Organization: Reed College, Portland, Oregon In article <3s9c0a$3mt@acmex.gatech.edu>, Kermit K. Murray wrote: > >I have been archiving the listserver posts for the the discussion group and >STMS in a searchable database available on WWW. The URL is reachable from the >MS page I have at http://tswww.cc.emory.edu/~kmurray/mslist.html (the one I >plugged in an earlier post). The search engine is a nice add-on to MacHTTP >and it is running on one of my lab Macintosh computers. I'll keep on >archiving server posts as much as time an disk space permits. Thanks- Been there once and it looks good! -Jay Beale jbeale@reed.edu -- -Jay Beale jbeale@reed.edu jbeale@epitope.com (not private, limited access) ****************************************************************************** From: dhachey@bcm.tmc.edu Subject: Re: Hello, mass spectrometric world. Date: 23 Jun 1995 20:17:11 GMT Organization: Baylor College of Medicine > jesnow@geobar.mpch-mainz.mpg.de (Jonathan E. Snow) writes: > I'm very happy the CFV went through and I'm grateful to whoever had > the initiative to put it through. > > As an isotope geochemist, mass spectometry is the major tool I use in > my work on the radiogenic isotopes of Pb, Sr, Nd and Os. Mostly, the > technology of solid source mass spectrometers has been stable for > about the past 40 years, since the late AO Nier invented the magnetic > sector analyzer. Recently, there have been some new developments > which may change all that, and I hope to discuss that a little in this > space. [Snip, snip] >>>> Jon; I think many of us in the isotope business mourn the passing of Al Nier. I agree with your statement that the basic design isotope ratio magnetic sector has remained unchanged for a while. I think most of us would also agree that improvements in collector geometry (i.e., multicollectors), electromics, and data systems have improved our lot over the past 20 yr or so. Those of us in the biomedical arena probably don't have the same perspective as geochemists, however. Please discuss your ideas on improvements in isotope ratio measurements. That's what this forum is for. Regards, Dave Hachey ****************************************************************************** From: "Thomas A. Lehman" Subject: Re: Can the chemical mass defect be measured by weighing ? Date: Fri, 23 Jun 1995 18:52:44 -0400 Organization: Duke University, Durham, NC, USA In-Reply-To: <3scica$kje@acmex.gatech.edu> On 22 Jun 1995, Kermit K. Murray wrote: > Date: 22 JUN 1995 16:04:26 -0400 > From: Kermit K. Murray > Newgroups: sci.techniques.mass-spec, sci.chem, sci.physics > Subject: Re: Can the chemical mass defect be measured by weighing ? > > I'm forwarding this to sci.techniques.mass-spec. Cross-post replies to > sci.chem and sci.physics. > > Joel Polowin wrote: > :vanesch@dice2.desy.de (Patrick P. E. Esch) wrote: > : > :: Howdy ! Sorry, but the "energy released in a chemical reaction" > :: has a mass defect just as well as the nuclear variety. > :: Meaning: YES, H2O is a little bit lighter than 1/2(2 H2 + 02). > :: And the difference in weight would be dm = dE / c2 with dE the > :: amount of energy released by burning H2. > :: Only, as the masses of the atoms are of the order of 1GeV > :: and the energy of the order of a few eV, this would be a > :: 10-9 effect, and I don't think it is possible to weight something > :: with an accuracy of 10 digits. > : > :I have been told that some mass-spectroscopy group is able to measure > :a mass difference between, say, a structure with a double bond and > :the same atoms arranged in a cyclic structure, because of the > :difference in bond energies. I remain profoundly skeptical, for > :reasons similar to your calculation above. > : > :Then again, Mossbauer spectroscopy works by doppler-shifting gamma > :radiation (3E8 m/s) by amounts on the order of a few cm per second > :(~3E-2 m/s). I won't simply dismiss these claims out of hand. > : > :Joel > :polowin@hyper.com > :http://www.hyper.com > : > > Kermit K. Murray > kmurray@emory.edu > http://tswww.cc.emory.edu/~kmurray/ > IT HAS BEEN AT LEAST TWO YEARS since I last heard Alan Marshall speak or read his work in current journals. The measurement in question is "the holy grail" in his lab, and at last report he was within a power of ten of success, if my memory is correct. This is a quick reply -- I have not tried to get my hands on a lit reference. But he may have put this in print in an article on Fourier transform mass spectrometry in Analytical Chemistry within the past three years. Thomas Lehman Duke University Med Center Mass Spectrometry Lab ****************************************************************************** From: mcbrp@leonis.nus.sg (Philp Robin John) Subject: Peptide/Protein ionisation? Date: 24 Jun 1995 03:08:12 GMT Organization: National University of Singapore Summary: Keywords: Greetings, Good to see this digest up and running, great job. As a non MS user but one that has samples analysed by this technique (electrospray/API/LC/MS) I would like to seek info. My work involves the isolation of peptides and proteins for sequence analysis using chemical degredation techniques. Most proteins are digested in-gel and peptides separated using micro-reversed phase HPLC. I almost always use Trifluoroacetic acid as an ion pair reagent in the eluting solvents (water for A and acetonitrile for B) as this gives an excellent separation. However, I don't get much success when I submit a small amount of each fraction for MS analysis. If I have already carried out a separation the samples are usually applied by flow injection in 60% ACN. One reason offered is that TFA suppreses ionization of the peptide and formic acid would be better. I can switch to this but have read many references for this work being carried out perfectly well in TFA. Does anybody have any thoughts or comments on this effect that would be happy to post? It would be very useful to obtain mass data on the peptides before sequencing so as to help in full analysis. Apologies if this has appeared before but I posted a similar message before this link was fully up and running and I think it may have got lost! Many thanks. Robin J. Philp Institute for Molecular and Cell Biology Singapore. ****************************************************************************** From: gmt1810@trex.oscs.montana.edu (Mark Tarka) Subject: Re: Anybody out there? Date: Sat, 24 Jun 1995 22:40:18 Organization: Montana State University In article <3s3v2o$pnt@acmex.gatech.edu>, "A.L. McCormack" writes: [Snip...] >I am getting ready to do H-D exchange of a protein followed by >micro-LC-ESI. Anyone have any general hints or suggestions? [Snip...] Hove you talked with the NMR people (H-D exchange is a routine deal)? Mark gmt1810@msu.oscs.montana.edu ****************************************************************************** From: depauw@gw.unipc.ulg.ac.be (De Pauw Edwin) Subject: peptides sequencing Date: Mon, 26 Jun 1995 15:09:04 +0200 Organization: Liege University Oligopeptides sequencing can be performed using liquid SIMS or electrospray ionization. If the interpretation of spectra of known compounds is easy, structure determination of unknowns is however not so direct. Fragmentation does not often give all the structural information needed. Two methods can then be used: the brutal force or MS/MS. The brutal force means fitting the spectra on the basis of the amino acids combinations. If their nature can be deduced from the low mass iminium fragments, the task is simplified. The other way is the use of MS/MS. Daughter ion spectra are usually employed. We used in addition the fact that b-a ions are often present to selectively pick the b-a transition by constant neutral loss of CO. This scan labels the fragments as b ones. In electrospray, multiply charged ions are the source of most fragments. We recently observed the loss of CO and water from doubly charged ions on a triple quadrupole instrument, resulting, as expected, from the apparent loss of half the mass monitored (double charge). In sector instruments, the same sample gaves not the same results. We think that calibration of linked scans do not work for losses from multiply charged ions. Before to start ourselves the scans calculation, we would like to know if someone already made the job. Thanks -- De Pauw Edwin Mass Spectrometry Laboratory, B6 Chemistry Institute, Liege University B4000-Liege Belgium depauw@gw.unipc.ulg.ac.be ****************************************************************************** From: jts@sage.cc.purdue.edu (Jon Schwedler) Subject: Re: Peptide/Protein ionisation? Date: 26 Jun 1995 11:42:55 -0500 mcbrp@leonis.nus.sg (Philp Robin John) writes: >Greetings, >Good to see this digest up and running, great job. >As a non MS user but one that has samples analysed by this technique >(electrospray/API/LC/MS) I would like to seek info. >My work involves the isolation of peptides and proteins for sequence >analysis using chemical degredation techniques. Most proteins are >digested in-gel and peptides separated using micro-reversed phase HPLC. I >almost always use Trifluoroacetic acid as an ion pair reagent in the >eluting solvents (water for A and acetonitrile for B) as this gives an >excellent separation. However, I don't get much success when I submit a >small amount of each fraction for MS analysis. If I have already carried >out a separation the samples are usually applied by flow injection in 60% >ACN. One reason offered is that TFA suppreses ionization of the peptide >and formic acid would be better. I can switch to this but have read many >references for this work being carried out perfectly well in TFA. >Does anybody have any thoughts or comments on this effect that would be >happy to post? It would be very useful to obtain mass data on the >peptides before sequencing so as to help in full analysis. >Apologies if this has appeared before but I posted a similar message >before this link was fully up and running and I think it may have got lost! >Many thanks. >Robin J. Philp >Institute for Molecular and Cell Biology >Singapore. Before my research group scampered away to another university, they typically dried their peptides down, then re-constituted with water (0.1%TFA). Hope it helps! JT ****************************************************************************** From: jts@sage.cc.purdue.edu (Jon Schwedler) Subject: Re: Peptide/Protein ionisation? Date: 26 Jun 1995 11:42:55 -0500 mcbrp@leonis.nus.sg (Philp Robin John) writes: >Greetings, >Good to see this digest up and running, great job. >As a non MS user but one that has samples analysed by this technique >(electrospray/API/LC/MS) I would like to seek info. >My work involves the isolation of peptides and proteins for sequence >analysis using chemical degredation techniques. Most proteins are >digested in-gel and peptides separated using micro-reversed phase HPLC. I >almost always use Trifluoroacetic acid as an ion pair reagent in the >eluting solvents (water for A and acetonitrile for B) as this gives an >excellent separation. However, I don't get much success when I submit a >small amount of each fraction for MS analysis. If I have already carried >out a separation the samples are usually applied by flow injection in 60% >ACN. One reason offered is that TFA suppreses ionization of the peptide >and formic acid would be better. I can switch to this but have read many >references for this work being carried out perfectly well in TFA. >Does anybody have any thoughts or comments on this effect that would be >happy to post? It would be very useful to obtain mass data on the >peptides before sequencing so as to help in full analysis. >Apologies if this has appeared before but I posted a similar message >before this link was fully up and running and I think it may have got lost! >Many thanks. >Robin J. Philp >Institute for Molecular and Cell Biology >Singapore. Before my research group scampered away to another university, they typically dried their peptides down, then re-constituted with water (0.1%TFA). Hope it helps! JT ****************************************************************************** From: "kasi V. Somayajula" Subject: Re: ICP-MS Analyses Service? Date: 26 Jun 1995 20:37:14 GMT Organization: University of Pittsburgh pggreen@cco.caltech.edu (Peter G. Green) wrote: >Howdy, > >I'm looking for recommendations of commercial services that will do >ICP-MS analyses. US and/or Canada preferred. Needing pbb and ppt >performance. > > I know one company that can help you ANTECH Ltd in Pittsburgh ONE TRIANGLE DRIVE EXPORT, PA 15632 1-800-78-EARTH Good Luck Kasi ****************************************************************************** From: raj@alumni.caltech.edu (Roger Moore) Subject: Re: Peptide/Protein ionisation? Date: 26 Jun 1995 22:01:39 GMT Organization: California Institute of Technology, Pasadena mcbrp@leonis.nus.sg (Philp Robin John) writes: >As a non MS user but one that has samples analysed by this technique >(electrospray/API/LC/MS) I would like to seek info. >My work involves the isolation of peptides and proteins for sequence >analysis using chemical degredation techniques. Most proteins are >digested in-gel and peptides separated using micro-reversed phase HPLC. I >almost always use Trifluoroacetic acid as an ion pair reagent in the >eluting solvents (water for A and acetonitrile for B) as this gives an >excellent separation. However, I don't get much success when I submit a >small amount of each fraction for MS analysis. If I have already carried >out a separation the samples are usually applied by flow injection in 60% >ACN. One reason offered is that TFA suppreses ionization of the peptide >and formic acid would be better. I can switch to this but have read many >references for this work being carried out perfectly well in TFA. The MS lab where I work does just fine using TFA sltns. In fact, they do quite well with a capillary column HPLC feeding directly into the ESI for our triple quads, and that uses TFA as an ion pair reagent. I wouldn't think that the TFA would be a problem. -- Raj Master of Meaningless Trivia ****************************************************************************** From: wendyab@mail.utexas.edu Subject: HELP!! Arachidonic Acid and Deuterium Date: 27 Jun 1995 01:11:48 GMT Organization: The University of Texas at Austin I need to find a GCMS method for determining synthesis of arachidonic acid that uses incorporation of deuterium labeling. I've found a few things on synthesizing deuterated arachidonic acid, but nothing on which ions to monitor, etc. If I can't find a method, I have to do something else for my thesis project. HELP!!! Thank you in advance for any help you may have. ****************************************************************************** From: mroz@Lanl.GOV (Eugene Mroz) Subject: Slurry Analysis by ICP/MS or ICP/AES Date: Tue, 27 Jun 1995 08:14:09 -0700 Organization: Los Alamos National Laboratory Does anyone have experience with analzying aqueous slurries of NIST SRM 1648 (Urban Particulate) by ICP/MS or ICP/AES methods? I'd like to hear about your experiences and results. I've been trying-but with little success. Thanks! -- Gene Mroz + Voice: 505-667-7758 Chemical Science and Technology Division + Fax: 505-665-4955 Mail Stop: J514 + E-Mail: mroz@lanl.gov Los Alamos National Laboratory Los Alamos, NM 87545 "There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact"--Mark Twain from Life on the Mississippi ****************************************************************************** From: dip@hubcap.clemson.edu Subject: Selected Ion Monitoring v. Extracted Ion Date: 27 Jun 1995 14:49:38 GMT Organization: bizzzarro rancho I am using a HP 5890/5971MSD to look at pyrrolic nitrogen heterocycles in crude oil. My problem is this: when using SIM to monitor alkylated three and four ring compounds, I find that as the amount of alkylation increases(ie from C1 to C2, etc.) that I'm getting each new peak in addition to those already being monitored. This mixture is extremely complex, with many isomers of each and up to C11-carbazoles and C8-benzocarbazoles present above my current detection limits. These compounds do not all elute in order of alkylation/mass (seems obvious you say), so I can't "turn one ion off" while "turning another ion on". Basically, I need to monitor for all of the various alkylated ions of carbazole(181,195,209,223,etc.) over a 12 minute window and then all of the alkylated isomers of benzocarbazole over a diffent, later 15 minute window of elution. But this doesn't allow me to determine if the peaks are one compound or two different alkylated species(eg C3 and C4). My question: What is the difference between Extracted ion monitoring from the TIC and SIM in terms of data quality? Is Extracted Ion as "good" as SIM? If I use Extracted Ion on my standards, shouldn't that behave the same as SIM of the standards? sorry this is rather jumbled and not all that clear(late night last night, but aren't they all?) I'd be more than willing to reference any help given in my thesis. also any good references would be appreciated. admittedly, I'm still in the process of searching the literature on this subject, so try not to flame me for missing something obvious. I'm really looking mostly for personal experiences here. Gracias, dip "Help! Help! I'm being repressed! / Come and see the violence inherent in the system!!" ****************************************************************************** From: KKM Subject: Re: this years ASMS meeting Date: 27 Jun 1995 21:42:11 GMT Organization: Emory University Chemistry This was posted in sci.chem a few weeks ago. Somewhat off-topic, but it was part of an ASMS plenary talk. [begin paste] Subject: (fwd) Top Ten reasons Network Producers don't give science more air time! At the latest ASMS meeting in Atlanta GA Miles O'Brien presented to us: FROM THE HOME OFFICE IN LOS ALAMOS, NEW MEXICO, THE TOP TEN REASONS NETWORK NEWS PRODUCERS DON'T GIVE SCIENCE MORE AIR TIME. NUMBER TEN: "ALREADY DID THE O.J. DNA FINGERPRINT STORY." NUMBER NINE: "'BUCKY BALLS' EXPUNGED FROM SCRIPTS BY NERVOUS NETWORK CENSORS." NUMBER EIGHT: "WAITING FOR COLD FUSION." NUMBER SEVEN: "WOULDN'T KNOW THE SUPER CONDUCTING SUPERCOLLIDER FROM A HOLE IN THE GROUND." NUMBER SIX: "STILL THINK SCIENCE'S GREATEST ACHIEVEMENT WAS TANG." NUMBER FIVE: "FEEL GUILTY BECAUSE OZONE HOLE LINKED TO EXCESSIVE HAIR SPRAY USE BY NEWS ANCHORS." NUMBER FOUR: "POCKET PROTECTORS CAUSE TOO MUCH GLARE UNDER HARSH TV LIGHTS." NUMBER THREE: "BRAINWASHED BY BIOSPHERIANS." NUMBER TWO: "UNABLE TO LOCATE FILE FOOTAGE OF THE 'BIG BANG.'" AND THE NUMBER ONE REASON NETWORK NEWS PRODUCERS DON'T GIVE SCIENCE MORE AIR TIME: "JOURNALISTS ARE FROM MARS...SCIENTISTS FROM VENUS." Miles O'Brien ASMS meeting 1995 Anders Lund -- ><> Anders Lund <>< alund@unl.edu <>< [end paste] Kermit K. Murray mailto:kmurray@emory.edu http://tswww.cc.emory.edu/~kmurray/ ****************************************************************************** From: douglas@chem.ubc.ca (don douglas) Subject: ASMS 1996 Date: 27 Jun 1995 20:21:31 GMT Organization: University of British Columbia When is the ASMS 1996 meeting? -- Don Douglas Chemistry University of British Columbia 2036 Main Mall Vancouver,B.C. V6T 1Z1 ****************************************************************************** From: jbeale@reed.edu (Jay Beale) Subject: Re: Selected Ion Monitoring v. Extracted Ion Date: 27 Jun 1995 23:31:10 GMT Organization: Reed College, Portland, Oregon The essence of the difference is that in scan mode you are looking at all the ions in the scan range, whether they yield valuble information or not, while in SIM mode you only look at predetermined ions. I'm sure you know that already, but what it boils down to is the machine performs more measure- ments per ion per minute in SIM mode than it does in scan mode. As far as data quality, I've heard that quantitation suffers if one has less than 11 (I've also heard 13) data points across the width of the peak being measured. The HP manual has a section on how to figure out the number of data points your method will collect, so that's a good place to start. Your standard curve data must be collected using the same method as used for the unknowns. Let me know if you need more info... -Jay Beale jbeale@reed.edu In article <3spicp$98b@acmex.gatech.edu>, wrote: >I am using a HP 5890/5971MSD to look at pyrrolic nitrogen heterocycles in >crude oil. >My question: What is the difference between Extracted ion monitoring from the >TIC and SIM in terms of data quality? Is Extracted Ion as "good" as SIM? If I use >Extracted Ion on my standards, shouldn't that behave the same as SIM of the >standards? >Gracias, >dip >"Help! Help! I'm being repressed! / Come and see the violence inherent in the >system!!" > > > -- -Jay Beale jbeale@reed.edu jbeale@epitope.com (not private, limited access) ****************************************************************************** From: dfettero@pipeline.com (Dean Fetterolf) Subject: Re: Selected Ion Monitoring v. Extracted Ion Date: 27 Jun 1995 21:31:18 -0400 Organization: The Pipeline As you have noticed Extracted ion profiles are useful for "profile" comparison and compound class feature extraction. SIM however will improve your S/N ratio but at the loss of full spectral data. ****************************************************************************** ****************************************************************************** From: gmt1810@trex.oscs.montana.edu (Mark Tarka) Subject: Re: Electrospray for the monitoring of photochemical reactions Date: Tue, 27 Jun 1995 19:42:53 Organization: Montana State University In article <3sci81$j8f@acmex.gatech.edu>, depauw@gw.unipc.ulg.ac.be (Edwin De Pauw) writes: [Snip...] >Post column derivatization is often used to increase detection sensitivity >and selectivity. The postcolumn photoaddition can be used to selectively >label the photoreactive compound before its entrance into the ion source. >Coupled with a MS/MS scan, it allows the specific detection of the target >compound or its quantification by MRM (multiple reaction monitoring) Wouldn't that specific photo-tag make UV detection the desirable choice? Could you elaborate a bit about MS/MS and its connection to MRM, and about the MRM process itself; a citation or two to a major journal would suffice. I'd like to get a feel for what you mean by quantitation (e.g. reproducibility and accuracy) using the electrospray method. Right now I have the impression that short term analyses are doable, while long term, repetitive work is not. TIA Mark gmt1810@msu.oscs.montana.edu ****************************************************************************** From: URWFOSTER@MSUVX1.MEMPHIS.EDU Date: Tue, 27 Jun 1995 22:02:06 -0500 (CDT) Subject: Balzers Help Needed for Quad Mass Sp. From: urwfoster@cc.memphis.edu Subject: Balzers Help Needed for Quad Mass Sp. Date: 27 Jun 95 22:00:51 -0500 Followup-To: sci. techiques. Keywords: Balzers Organization: The University of Memphis News-Moderator: Approval required for posting to sci.techniques.mass-spec I have a Balzers QMG 112 powersupply, rga, preamp. and have lost the manual, can anyone lend some assistance to me? All respondents would be greatly appreciated. ****************************************************************************** From: macht@chclu.chemie.uni-konstanz.de (Marcus Macht) Subject: Re: Anybody out there? Date: 28 Jun 1995 07:52:47 GMT Organization: Univ.Konstanz,Germany A.L. McCormack wrotes: >[Snip...] >>I am getting ready to do H-D exchange of a protein followed by >>micro-LC-ESI. Anyone have any general hints or suggestions? >[Snip...] I think you should try H-D exchange without LC-ESI first, because you shurely will have a remarkable back-exchange in the LC. We use for our exchange experiments solutions of proteins in deuterated solvents (D2O, D4-acetic acid, ND4OD etc.) with flow injection on a vestec instrument. Before making your LC-ESI experiments, you should investigate , how much protons exchange fast or very fast 'cause I would expect that these will back-exchange in your chromatography prior to MS. Marcus Macht Faculty of chemistry University of Constance Germany ****************************************************************************** From: cepas@randb.pprd.abbott.com Subject: Vestec electrospray Date: 28 Jun 95 07:16:10 CST Organization: Abbott Laboratories I'm happy to see this group up and running finally! Thanks Dave. I'm having trouble running LC/MS with a Vestec ESI interface. Using the interface in infusion mode with a syringe pump, things seem pretty good -- picomole sensitivity for small peptides (under 2000 da), usually just the single and doubly charged ions. However when I switch to LC/MS using an Acurate flow splitter, the sensitivity goes out the window, losing maybe a factor of 1000. Can anyone offer any tips? On the Vestec ESI interface, or the Acurate splitter? Details: Extrel triple quad Waters 600MS series HPLC Acurate splitter @ the 1:50 or 1:150 splits column flow of 250 uL/min 25:75 ACN:25mM NH4OAc post-column flow of 400 uL/min of 5% HOAc in MeOH flow into ESI @ 1:50 split = 13 uL/min flow into ESI @ 1:150 split = 4.3 uL/min HPLC backpressure about 1500psi with 2mm column I plan on measuring the actual split today. Any other ideas? -- ***************************************************************************** Steve Cepa ++Just a thought++ Abbott Labs *** These are my opinions only. So blame me. *** (midway between Chicago and Milwaukee) cepa.steven@igate.abbott.com The most significant exclaimation in scientific disovery is not "Eureka", but "That's funny..." (Isaac Asimov) ***************************************************************************** ****************************************************************************** From: URWFOSTER@MSUVX1.MEMPHIS.EDU Date: Tue, 27 Jun 1995 22:02:06 -0500 (CDT) Subject: Balzers Help Needed for Quad Mass Sp. From: urwfoster@cc.memphis.edu Subject: Balzers Help Needed for Quad Mass Sp. Date: 27 Jun 95 22:00:51 -0500 Followup-To: sci. techiques. Keywords: Balzers Organization: The University of Memphis News-Moderator: Approval required for posting to sci.techniques.mass-spec I have a Balzers QMG 112 powersupply, rga, preamp. and have lost the manual, can anyone lend some assistance to me? All respondents would be greatly appreciated. ****************************************************************************** From: Erich Loew Subject: pc-utilities for interpretation of mass spectra available? Date: 27 Jun 1995 12:50:23 GMT Organization: Leibniz-Rechenzentrum, Muenchen (Germany) NNTP-Posting-Host: 141.84.241.24 I am looking for a simple program which should help me to assign peaks in a mass spectra. For example: I find a peak at 262 m/e and want to know which combination of elements could give a mass of 262. If I know that only carbon, hydrogen and oxygen are present in my molecule, the program should be able to propose the formula: C15 H18 O4 (of course together with other possible combinations). The program should run under dos or windows. Please mail me if you know on which ftp-server there's something like that: email: eel@org.chemie.uni-muenchen.de ****************************************************************************** From: pggreen@cco.caltech.edu (Peter G. Green) Subject: Re: ASMS 1996 Date: Wed, 28 Jun 95 22:15:25 GMT Organization: Caltech (Environmental Engineering Science) >When is the ASMS 1996 meeting? > >[The 1996 ASMS conference will be in Portland, Oregon, from May 12-17. - db] How might one get more information about attending? Post or email. Thanks in advance. -Peter Green ****************************************************************************** From: Fred Schwarzer Subject: Re: pc-utilities for interpretation of mass spectra available? Date: 29 Jun 1995 07:37:17 GMT Organization: Institute of Food Chemistry / Technical University of Berlin There is a publication that may help you. The programs can be obtained from the authors. I4m also interested in that programs. So i would be pleased if you can send me a note when you get these programs. Title [ Simple Tools for computer-aided interpretation of mass spectra ] Authors[ Silvia Heuerding, Jean Thomas Clerc ] Source [ Chemometrics and Intelligent Laboratory Systems, 20 (1993) 57-69 ] Abstract[ Simple Programs to obtain from low-resolution mass spectra self-consistent sets of plausible estimates for the molecular mass and the elemental composition of the more important peaks are described. The algorithms used are given in detail.] -- Fred Schwarzer Institute of Food Chemistry / TU Berlin see also http://kojak.lb.tu-berlin.de/lc/fred.htm ****************************************************************************** From: wenthold@dante.colorado.edu Subject: Re: ASMS 1996 Date: 29 Jun 1995 15:44:44 GMT Organization: University of Colorado at Boulder In-Reply-To: pggreen@cco.caltech.edu's message of 29 Jun 1995 08:27:55 -0400 >When is the ASMS 1996 meeting? > >[The 1996 ASMS conference will be in Portland, Oregon, from May 12-17. - db] How does everyone feel about the fact that the Portland meeting will be at the convention center and not a hotel? What effect will this have on the meeting? What about conference fees? Will they go up? Will this turn people off and end up making the meeting smaller? What will happen to the format? Can we handle extra oral sessions going on at the same time? I'm sure the poster sessions can handle getting bigger... paul PS What's gong to happen to the hospitality suites? -- *********************************************************************** * * * * Dr. Paul G. Wenthold * "Not many girls in contemporary * * JILA * society would give their underwear * * University of Colorado * to help a geek like me." * * Boulder, CO 80309 * Farmer Ted * * (303)492-7768 * * * * * *********************************************************************** * I don't speak for JILA. In fact, I doubt they even agree with me! * *********************************************************************** ****************************************************************************** From: db32@prism.gatech.edu (David E. Bostwick) Subject: Re: ASMS 1996 Date: 29 Jun 1995 16:07:38 -0400 Organization: Georgia Institute of Technology In article <3suqis$pv4@acmex.gatech.edu>, wrote: : : : >When is the ASMS 1996 meeting? : > : >[The 1996 ASMS conference will be in Portland, Oregon, from May : 12-17. - db] : : :How does everyone feel about the fact that the Portland meeting :will be at the convention center and not a hotel? What effect :will this have on the meeting? What about conference fees? :Will they go up? Will this turn people off and end up making the :meeting smaller? What will happen to the format? Can we handle :extra oral sessions going on at the same time? I'm sure the poster :sessions can handle getting bigger... : :paul : :PS What's gong to happen to the hospitality suites? I was told that the best option was to use a convention center. The meeting has grown so large that only a few hotels are large enough to hold it, and splitting up into separate hotels was a worse choice. As for fees and hospitality suites, any changes will obviously depend on what the cost of the convention center is. I know there are people who read this who are on the Board, or who have regular contact with them, as well as company reps. Any word from y'all? -- David E. Bostwick Georgia Institute of Technology, Atlanta, GA, 30332 david.bostwick@chemistry.gatech.edu ****************************************************************************** From: nomad01@aol.com (Nomad01) Subject: Re: Selected Ion Monitoring v. Extracted Ion Date: 29 Jun 1995 18:22:46 -0400 Organization: America Online, Inc. (1-800-827-6364) Your Question: My question: What is the difference between Extracted ion monitoring from the TIC and SIM in terms of data quality? Is Extracted Ion as "good" as SIM? If I use Extracted Ion on my standards, shouldn't that behave the same as SIM of the standards? 1st Part: The quality of the TIC versus SIM monitoring is mostly dependant upon the relative sensitivity of the MSD to the analyte(s). In general, I prefer to use SIM for routine analytical use because of sensitivity issues but if you have adequate sensitivity to perform your analysis in TIC mode you have more reliable data upon which to establish compound identity. 2nd part The quality of the ion, be it extracted or SIM, is mostly related to how well the inital paramenters have been established. Dwell time is very important to prevent biasing of the spectra. (This is most apparent when your isotopic ratios are incorrect.) If you do go with SIM mode it is VERY important to perform a Dynamic Mass Calibration for the SIM ions of interest. 3rd Part I would not reccomend that approach because of relative sensitivity differences between the two modes. An exception might be if you are using an internal standard for correction of injection variation. I have been using and developing analytical methods for pesticides using the 5971 for about five years now. It's a tough instrument. I would appreciate hearing more as I am not sure that I understood all of the details of your application. Feel free to EMAIL me. Hope this helps, Mike Hope this helps, ****************************************************************************** From: deline@netcom.com (James Deline) Subject: Re: pc-utilities for interpretation of mass spectra available? Organization: NETCOM On-line Communication Services (408 261-4700 guest) Date: Thu, 29 Jun 1995 22:31:54 GMT Erich Loew (eel@org.chemie.uni-muenchen.de) wrote: : [This was posted in sci.chem. I've directed him here, but a cross-post to : sci.chem would probably also be helpful. - db] : I am looking for a simple program which should help me to assign : peaks in a mass spectra. : For example: : I find a peak at 262 m/e and want to know which combination of : elements could give a mass of 262. : If I know that only carbon, hydrogen and oxygen are present in my : molecule, the program should be able to propose the formula: : C15 H18 O4 (of course together with other possible combinations). : The program should run under dos or windows. I've written a program that does exactly that, but it is currently only available on the Macintosh. However, someone is porting it over to Windows and we hope it will be done with the next month or two. Both versions will be freeware. The mac version can be ftp'd from: ftp.netcom.com/pub/de/deline/ The name of the program file is MFCalc jd ****************************************************************************** Date: Thu, 29 Jun 1995 15:05:17 -0700 (PDT) From: Lorne Isabelle Subject: ASMS Portland I tried to post this but it didn't fly. It turns out the daughter of the Chemistry Dept secretary here at OGI is the representative for the Portland Convention Center. From what I can figure out, they are going to use 3 to 4 hotels near the convention center. The hospitality suites will be at the convention center, or at least that option is available. I think that by the time the convention rolls around, the Portland light rail will be free in the downtown area so getting from hotels to the convention center will be no problem. Some are within walking distance. I think this will all workout O.K. Lorne Isabelle Oregon Graduate Institute ****************************************************************************** From: G.Spierings@fys.ruu.nl (Geert Spierings) Subject: H/Cu pair potentials wanted. Organization: Physics and Astronomy, University of Utrecht, The Netherlands Date: Fri, 30 Jun 1995 12:31:19 GMT Date: 30 Jun 95 12:23:01 GMT Subject: H/Cu pair potentials wanted. We are looking for a reliable pair potential to be able to calculate trajectories for hydrogen atoms, being scattered off a Cu single crystal surface. The energies of the H atoms will be from 1 keV to 5 keV, and the H atoms are grazingly incident onto the surface, so in this energy regime most of the H-atoms will stay above the surface. We have done some 'screened coulomb' and 'moliere' potential calculations, but we don't know exactly how valid these are. The exact trajectory is very important to us. So what we want is pair potentials for the H / Cu collision system, valid under the experimental conditions mentioned above. Thanks for your time, Geert. ----------------------------------------------------------------------- Geert Spierings Debye Institute Princetonplein 5 spiering@fys.ruu.nl 3584 CC Utrecht, NL ----------------------------------------------------------------------- -- ----------------------------------------------------------------------- Geert Spierings Debye Institute Princetonplein 5 spiering@fys.ruu.nl 3584 CC Utrecht, NL ----------------------------------------------------------------------- ****************************************************************************** From: dpvw@iastate.edu (Dave P VanderWiel) Subject: Re: ASMS 1996 Date: 30 Jun 1995 14:40:18 GMT Organization: Iowa State University, Ames, Iowa USA Originator: dpvw@eng3.iastate.edu In article <3suqis$pv4@acmex.gatech.edu>, wenthold@dante.colorado.edu writes: |> |> |> How does everyone feel about the fact that the Portland meeting |> extra oral sessions going on at the same time? I'm sure the poster |> sessions can handle getting bigger... |> |> paul |> |> PS What's gong to happen to the hospitality suites? Yeah - what about the hospitality suites!?!?!?!?!? Dave ****************************************************************************** From: Ashley McCormack Subject: Re: Peptide/Protein ionisation? Date: Fri, 30 Jun 1995 08:38:24 -0700 Organization: University of Washington Nntp-Posting-User: alm7203 In-Reply-To: <3smcjb$4hb@acmex.gatech.edu> Finally a newsgroup!!!! Anyway I have several questions to clarify: if you separate peptides by HPLC then you use direct injection in 60% MeCN to introduce sample into MS? Do you lyophylize (sp?) your sample to dryness?? Is the instrument tuned properly for TFA/MeCN? We usually run fractions on a micro-LC/ESI/MS system that uses acetic acid as solvent A. And we do not have a problem with TFA as it is usually washed off the column before acquisition. -Ashley ********************************** Ashley L. McCormack Research Scientist III Dept. of Molecular Biotechnology FJ-20, University of Washington Seattle, WA 98195 206-685-7335 alm7203@u.washington.edu http://thompson.mbt.washington.edu ********************************** On 26 Jun 1995, Philp Robin John wrote: > Greetings, > Good to see this digest up and running, great job. > > As a non MS user but one that has samples analysed by this technique > (electrospray/API/LC/MS) I would like to seek info. > > My work involves the isolation of peptides and proteins for sequence > analysis using chemical degredation techniques. Most proteins are > digested in-gel and peptides separated using micro-reversed phase HPLC. I > almost always use Trifluoroacetic acid as an ion pair reagent in the > eluting solvents (water for A and acetonitrile for B) as this gives an > excellent separation. However, I don't get much success when I submit a > small amount of each fraction for MS analysis. If I have already carried > out a separation the samples are usually applied by flow injection in 60% > ACN. One reason offered is that TFA suppreses ionization of the peptide > and formic acid would be better. I can switch to this but have read many > references for this work being carried out perfectly well in TFA. > > Does anybody have any thoughts or comments on this effect that would be > happy to post? It would be very useful to obtain mass data on the > peptides before sequencing so as to help in full analysis. > > Apologies if this has appeared before but I posted a similar message > before this link was fully up and running and I think it may have got lost! > > Many thanks. > > Robin J. Philp > Institute for Molecular and Cell Biology > Singapore. > > > > ****************************************************************************** From: David Wheeler Subject: Job Wanted. ICP-MS, LA-ICP-MS, GDMS Date: Fri, 30 Jun 1995 15:10:24 GMT Job Wanted ---------- I am looking for a challenging position in scientific instrument development. A micro CV follows. Name: David Wheeler Current Position: Project Scientist ICP-MS, LA-ICP-MS, GDMS Address: e-mail to wheeler@elementl.demon.co.uk Telephone U.K. 01606 861022, International +44 1606 861022 Nationality: British Age: 32 Qualifications: BSc Hons in Physics at Imperial College, London. Graduated 1984 Employment history in reverse chronolgical order. 1986 to 1995 (Current) F.I. Elemental (Formerly VG Elemental) * ICP-MS project scientist Part of a project team developming ICP-MS instrumentation. Sole desinger of an Ultra Violet laser ablation accessory for LA-ICP-MS. * GDMS product manager Product management of a high resolution GDMS instrument, the VG9000. * GDMS project scientist and applications scientist. GDMS development, both RF and DC for high resolution (VG9000) and quadrupole (GloQuad) GDMS instruments. Applications development and customer demonstrations for the VG9000 and GloQuad. * GDMS installation engineer. World wide installation and customer support for the VG9000 * Involvment in sales, marketing and customer care for ICP-MS and GDMS instruments. 1984 to 1986 G.E.C. Avionics - Applied Physics Division. * Operation of a gas analysis mass spec for H D T analysis. * Software development for the interpretation of mass spec data. Experience: In addition to my qualifications in physics I have gained considerable experience in a wide range of disciplines. These inclde: * Project managment. I have succesfully completed projects on time and in budget. * Mechanical engineering. I have experience in basic mechanical engineering and I am capable of generating my own mechanical drawings in AutoCad. * Lasers and optics. I have experience in NdYag, excimer and nitrogen lasers. I am also capable of designing basic optical systems. * Vacuum systems. I have extensive experience of vacuum systems design. * Sales and marketing. I have experience of direct instrument sales and marketing through visiting customers' sites to close orders, attending conferences to generate initial interest, writing instrument brochures and manuals and running demonstrations. * Software. I have some experience in programming and extensive experience of third party software including Lotus and Microsoft office sotware, AutoCad and AutoSketch, Ion Optics simulation, OS2 and Windows '95. * Customer care. I have extensive experience of solving customers' problems either during a site visit or through telephone support. * Systems engineering. As I have an understanding of many of the aspects of our business and experience in most of the disciplines involved I am in an excelent position to smoothly integrate each aspect of an instrument's development cycle. * Foreign Travel. I an familiar with the customs and business practice of many nationalities through first hand international travel. ****************************************************************************** From: Ashley McCormack Subject: Re: ASMS 1996 Date: Fri, 30 Jun 1995 09:06:49 -0700 Organization: University of Washington Nntp-Posting-User: alm7203 In-Reply-To: <3suqis$pv4@acmex.gatech.edu> I overheard a conversation about the hospitality suites being in the late afternoon/early evening at the convention hall. And how will people get safely back to their hotels after visiting all the suites? The meeting will be different. Might as well try it once. Ashley ********************************** Ashley L. McCormack, PhD Research Scientist III Dept. of Molecular Biotechnology FJ-20, University of Washington Seattle, WA 98195 206-685-7335 alm7203@u.washington.edu http://thompson.mbt.washington.edu ********************************** On 29 Jun 1995 wenthold@dante.colorado.edu wrote: > > > >When is the ASMS 1996 meeting? > > > >[The 1996 ASMS conference will be in Portland, Oregon, from May > 12-17. - db] > > > How does everyone feel about the fact that the Portland meeting > will be at the convention center and not a hotel? What effect > will this have on the meeting? What about conference fees? > Will they go up? Will this turn people off and end up making the > meeting smaller? What will happen to the format? Can we handle > extra oral sessions going on at the same time? I'm sure the poster > sessions can handle getting bigger... > > paul > > PS What's gong to happen to the hospitality suites? > -- > *********************************************************************** > * * * > * Dr. Paul G. Wenthold * "Not many girls in contemporary * > * JILA * society would give their underwear * > * University of Colorado * to help a geek like me." * > * Boulder, CO 80309 * Farmer Ted * > * (303)492-7768 * * > * * * > *********************************************************************** > * I don't speak for JILA. In fact, I doubt they even agree with me! * > *********************************************************************** > > > > ****************************************************************************** From: dejohnde@aol.com (DeJohnDE) Subject: Re: Peptide/Protein ionisation? Date: 1 Jul 1995 14:12:07 -0400 Organization: America Online, Inc. (1-800-827-6364) It is known that high levels of TFA suppresses the electrospray signal. LC/MS with 0.1% TFA is commonly used. Higher levels will start to cause problems. With isolated material, it is helpful to freeze-dry the material several times reconstituting with water between each freeze-drying. This removes excess TFA which may be left behind with inefficient freeze-driers. Dana DeJohn Parke-Davis 2800 Plymouth Rd. Ann Arbor, MI 48105 ****************************************************************************** From: jwindak@umich.edu (Jim Windak) Subject: Isotope pattern software Followup-To: sci.techniques.mass-spec Date: 5 Jul 1995 15:13:10 GMT Organization: University of Michigan, Chemistry Does anyone know of any software for Dos or Windows which will generate a theoretical isotope pattern from an entered formula? I have seen such programs for the Macintosh, but I would like to have a Dos or Windows version for one of our PC's which is interfaced to a GC/MS. Any suggestions would be appreciated. Jim Windak University of Michigan Chemistry Dept. jwindak@umich.edu ****************************************************************************** From: jwindak@umich.edu (Jim Windak) Subject: Isotope pattern software Date: 5 Jul 1995 15:13:10 GMT Organization: University of Michigan, Chemistry Does anyone know of any software for Dos or Windows which will generate a theoretical isotope pattern from an entered formula? I have seen such programs for the Macintosh, but I would like to have a Dos or Windows version for one of our PC's which is interfaced to a GC/MS. Any suggestions would be appreciated. Jim Windak University of Michigan Chemistry Dept. jwindak@umich.edu ****************************************************************************** Date: Wed, 05 Jul 1995 18:38:29 +0000 (GMT) From: ddxdd@IMAP1.ASU.EDU Subject: Re: Isotope pattern software Organization: daves not here Jim Windak (jwindak@umich.edu) wrote: : Does anyone know of any software for Dos or Windows which will generate a : theoretical isotope pattern from an entered formula? I have seen such : programs for the Macintosh, but I would like to have a Dos or Windows : version for one of our PC's which is interfaced to a GC/MS. Any : suggestions would be appreciated. PROCOMP is a program for protein analysis that includes an isotope ratio calculator (diophantine routine). the isotope pattern routine can handle all of the elements we have thrown at it (haven't tried the trans- uranics, though), with the caveat that you specify the number 1 for a single occurance of an element. the program can be obtained (free at last word) from: p.c. andrews, PhD room 2560a msrb-2 box 0674 univ. of michigan medical school ann arbor, mi 48109 the program is a dos program, but phil may be working on a windows version. oh, he requests that you write him for the program, NOT call him. hope this helps. -d^2 ****************************************************************************** From: Norbert Nieth Subject: Re: Isotope pattern software Date: 6 Jul 1995 13:28:21 GMT Organization: Organisch-Chemisches Institut boundary="-------------------------------28615894515740" This is a multi-part message in MIME format. ---------------------------------28615894515740 jwindak@umich.edu (Jim Windak) wrote: >Does anyone know of any software for Dos or Windows which will generate a >theoretical isotope pattern from an entered formula? I have seen such >programs for the Macintosh, but I would like to have a Dos or Windows >version for one of our PC's which is interfaced to a GC/MS. Any >suggestions would be appreciated. > >Jim Windak >University of Michigan >Chemistry Dept. >jwindak@umich.edu > > I am really interested in those pattern calculations, it ist not a trivial problem. I wrote a QBASIC program for DOS, which executes the job.I will attach a sample output of a caalculation. There is no graphical output but you can prit the data and save as ASCII-file. There is a conversion of decimal point to decimal comma and TAB-character creation included.This isbecause of the german version of my graphic software which only accepts decimal commama. Up to now there are 14 elements (the more important in our lab) in the table, but you can add or delete by your choice. The program is free, but you use on your own risc. There is no warranty because of algoryithm as well as inaccurate calculation depending on multiple multiplieing and adding small numbers. If anyone is interested, e-mail me and I will return the QBASIC Source code. Hope it will be easy to use, but I assist, if there are any questions Try and have time and fun. Norbert Nieth ---- Sample output of ISOTOP.BAS ------------ ---------------------------------28615894515740 Reconstructed Isotope Pattern of C27 H30 N1 O1 P1 Cl2 Pd1 Chemical Mass at 592,9733 Centroid Mass at 592,9732 Highest Clusterpeak at 593,0467 First Clustermass at 587,0491 Last Clustermass at 659,3230 Number of Clusterpeaks 24 Theoretical number of Clusterpeaks 93744 deltaM ,01 m/z rel. Int [%] 587,05 1,5474 588,05 ,4813 589,05 19,0734 590,05 49,6307 591,05 78,8430 592,05 50,7576 593,05 100,0000 594,05 33,6894 595,05 71,2870 595,06 ,0001 596,05 21,0301 597,05 25,7813 597,05 ,0008 598,05 7,3477 598,06 ,0020 599,05 3,9042 599,06 ,0001 600,05 ,9818 600,06 ,0002 601,05 ,1447 601,06 0,0000 602,05 ,0149 603,06 ,0012 604,06 ,0001 ---------------------------------28615894515740-- ****************************************************************************** From: db32@prism.gatech.edu (David E. Bostwick) Subject: no subject (file transmission) Date: Thu, 6 Jul 1995 09:51:27 -0400 (EDT) >From m13666@chaos.kulnet.kuleuven.ac.be Thu Jul 6 09:47:35 EDT 1995 Article: 41808 of sci.chem From: m13666@chaos.kulnet.kuleuven.ac.be (ilse vandecandelaere) Subject: NEED HELP ON HPLC-MS Date: 4 Jul 1995 12:10:38 GMT Organization: Katholieke Universiteit Leuven NNTP-Posting-Host: ipv13162.cc.kuleuven.ac.be I'm wondering wether I could identify thermal decomposition products of 2,4-pentanedione (HAA) by HPLC-MS. By HPLC only I'm able to detect HAA and acetic acid and two additional peaks. Is it possible to identify those additional peaks by HPLC-MS ? Probably they result from products with low molecular mass. Anyone any suggestions ?????? Thanks in advance, Ilse ****************************************************************************** From: Rachel Ogorzalek Looo Subject: re:re:isotope pattern software and protein software Date: 6 Jul 1995 17:18:10 GMT Organization: University of Michigan The DOS version of Procomp is still available free for the asking from Philip Andrews. e-mail address: andrews@brcf.med.umich.edu. Phil says it will handle the transuranics, although he didn't include ones for which the longest isotope half life was shorter than a second. Maybe he can be persuaded . . .The program also does protein mass maps, secondary structure calculations, and a wide range of primary structure calculations. It will also work on a MAC employing the "Soft PC" program. -------------- Rachel Ogorzalek Loo Protein and Carbohydrate Structure Facility University of Michigan 2560 MSRB II 1150 W. Meddical Center Dr. Ann Arbor, MI 48109-0674 ****************************************************************************** From: "Rob O'Brien" Subject: Re: Isotope pattern software Date: 6 Jul 1995 18:08:46 GMT Organization: National Research Council, Canada There is a web site available where you can calculate a isotope pattern from a formula it is at ; This will only give you the mass/intensity values and not a spectra. A more difficult problem is finding a program to calculate a pattern for an isotopically enriched species such as (37Cl)Cl5C12H4 where the 37Cl label is not 100%. If anyone has or knows of a program that can do that please let me know. regards, R.O'B ****************************************************************************** From: kkm Subject: Re: Isotope pattern software Date: 6 Jul 1995 20:24:01 GMT Organization: Emory University "Rob O'Brien" wrote: [snip] > A more difficult problem is finding a program to calculate a >pattern for an isotopically enriched species such as (37Cl)Cl5C12H4 >where the 37Cl label is not 100%. If anyone has or knows of a >program that can do that please let me know. There's a Macintosh shareware program Isotope Pattern Calculator v1.6.5 by Les Arnold (JANNINE@waikato.ac.nz) that allows isotope abundance editing and saves calculated abundance patterns as ASCII files. I haven't used it much, but it looks pretty good. It's on INFO-MAC at sumex-aim.stanford.edu by anonymous FTP or at the MIT hyperarchive URL below. Abstract: http://hyperarchive.lcs.mit.edu/HyperArchive/Abstracts/sci/isotope-patter n-calculator-165.hqx.abs Download: http://hyperarchive.lcs.mit.edu/HyperArchive/Archive/sci/isotope-pattern- calculator-165.hqx If that doesn't work, I have it on my software page at http://tswww.cc.emory.edu/~kmurray/mssw.html If anyone has a link to any other mass spec shareware, I can put it in there. Kermit K. Murray mailto:kmurray@emory.edu http://tswww.cc.emory.edu/~kmurray/ ****************************************************************************** From: senko@magnet.fsu.edu (Mike Senko) Subject: Re: Isotope pattern software Date: 7 Jul 1995 00:36:22 GMT Organization: NHMFL I wrote an isotope simulator in VB using Yergey's algorithm (IJMSIP, 52, 1983, 337-49) a couple of years back. It does all the elements (isotope ratios can be modified) and has graphical output to the screen and printer. Since it's written in VB, it's not real fast (ie. a 10 kDa protein takes 15 seconds to calculate the distribution and 20 to display on a 486/33), but I'm working on a new version in Delphi that should be 20x faster. If you want a copy of the old version, send me a note. I make no claims to the accuracy of the algorithm (you get what you pay for :), but Yergey was nice enough to give me his VAX Fortran code to translate, so it should be safe. All I know is that it matches experimental distributions from ESI-FTMS instruments real well. Note: I've not used the WWW distribution calculator myself, but I've heard it's results are a little off. Mike Senko senko@magnet.fsu.edu ****************************************************************************** From: a1619195@smail1.rrz.Uni-Koeln.DE (Werner Spahl) Subject: Re: NEED HELP ON HPLC-MS Date: 7 Jul 1995 12:10:55 GMT Organization: Regional Computing Center, University of Cologne ilse vandecandelaere (m13666@chaos.kulnet.kuleuven.ac.be) wrote: : : I'm wondering wether I could identify thermal decomposition products of : 2,4-pentanedione (HAA) by HPLC-MS. By HPLC only I'm able to detect : HAA and acetic acid and two additional peaks. Is it possible to : identify those additional peaks by HPLC-MS ? Probably they result from : products with low molecular mass. I would suggest to try it with HPLC/PB (Particle Beam)/MS. The Particle Beam will produce normal EI mass spectra of compounds from ~200-2000 amu. -- Werner Spahl (a1619195@smail.rrz.uni-koeln.de) "The meaning of my life is to make me crazy" ****************************************************************************** From: Rob Levine Subject: Wanted: Comprehensive Mass List for Quadrupole Gas Analyser Date: Fri, 07 Jul 1995 07:56:52 GMT Organization: Raychem Ltd Dear All, I routinely use quadrupole gas analysers and am after a comprehensive list of which species each mass is likely to represent. I already have various (incomplete) lists but was wondering if anyone new of a 'definitive' list. Thanks for any help, Rob -- Robert J. Levine. Corporate Technology Europe, Raychem Ltd, Faraday Road, Dorcan, Swindon, Wiltshire SN3 5HH, UK. ------------------------------------------------------- E-mail: rlevine@thinfilm.demon.co.uk OR rlevine@raukcte.ccmail.compuserve.com ****************************************************************************** From: strecker@chemie.fu-berlin.de (Andreas Strecker) Subject: Re: peptides sequencing Date: Fri, 07 Jul 95 20:09:04 GMT Organization: FU Berlin In article <3smd65$8bn@acmex.gatech.edu>, depauw@gw.unipc.ulg.ac.be (De Pauw Edwin) wrote: >Oligopeptides sequencing can be performed using liquid SIMS or >electrospray ionization. If the interpretation of spectra of known >compounds is easy, structure determination of unknowns is however >not so direct. Fragmentation does not often give all the structural >information needed. Two methods can then be used: the brutal force >or MS/MS. The brutal force means fitting the spectra on the basis of >the amino acids combinations. If their nature can be deduced from the >low mass iminium fragments, the task is simplified. The other way is >the use of MS/MS. Daughter ion spectra are usually employed. We used >in addition the fact that b-a ions are often present to selectively >pick the b-a transition by constant neutral loss of CO. This scan >labels the fragments as b ones. In electrospray, multiply charged ions >are the source of most fragments. We recently observed the loss of CO >and water from doubly charged ions on a triple quadrupole instrument, >resulting, as expected, from the apparent loss of half the mass monitored >(double charge). In sector instruments, the same sample gaves not >the same results. We think that calibration of linked scans do not work >for losses from multiply charged ions. Before to start ourselves >the scans calculation, we would like to know if someone already made >the job. >Thanks > There is also now the posiibility to sequence with MALDI-MS and post-source-decay (PSD) technique. The first machines are already on the market. The technique uses the "natural" fragmentation that occurs subsequent to acceleration of the ions after MALDI. The fragments get a secondary acceleration and are detectable as a fragmentation series of the original molecule. This makes peptide sequencing possible. Major advantages: Little sample amount required; low purity of sample required (peptide mixtures or even complete digest probes are sequencable); ions differing in less than 50 masses may be separated prior to sequencing within the MS by way of an electronic switch. Major disadvantage: Only few machines installed yet (but numbers are rapidly growing!) Andreas ****************************************************************************** From: brevardlab@aol.com (BrevardLab) Subject: Re: ICP-MS Analyses Service? Date: 7 Jul 1995 17:02:51 -0400 Organization: America Online, Inc. (1-800-827-6364) My lab also performs ICP-MS analysis. We have been using ICP-MS for about 4 years now doing primarily water and wastewater analysis but have had projects using isotope dilution, hydrothermal vent fluids and all sorts of solid materials ranging from steel to cement. We have recently started tissue analysis. Our mailing address is BTR Labs 250 Grassland Road SE Palm Bay FL 32909 407 632 1111 x22011 ****************************************************************************** From: sismspec@aol.com (Sismspec) Subject: Increasing Sensitivity of the HP MSD Date: 8 Jul 1995 12:19:39 -0400 Organization: America Online, Inc. (1-800-827-6364) Scientific Instrument Services has just published a 24 page, two part publication on improving the performance of the HP 5971 instruments. This paper was presented as a poster at the last AMMS meeting in Atlanta. This publication is free to anyone. E-mail us your name and address (sismspec@aol.com) or call us at 908-788-5550 and request the publication "Improving Sensitivity in the HP 5971 MSD and Other Mass Spectrometers" Part 1 of this article addresses the improvements that can be made in the MSD to improve its sensitivity (increasing signal-to-noise level). This can be accomplished by reducing the background originating in the MSD itself. The new high sensitivity multipliers available from several manufacturers were evaluated and provided a four to five fold increase in sensitivity over the original multipliers supplied with the MSD when it was first manufactured. Further improvements can be achieved by improving the vacuum level by using larger vacuum pumps and new higher grade rough pump and diffusion pump oils. A direct capillary transfer line was also used to permit the direct introduction of the column effluent into the GC source. Part 2 of this article describes the changes that can be made to the GC to improve performance. GC bleed is the major reasons for loss in MS sensitivity because any bleed from the column or injection port contributes to the background noise level in the MSD. GC septa from various manufacturers were studied and it was determined that the Supelco Thermogreen septa produce the lowest bleed for use in GC/MS applications. A new injection port liner and Vespel injection port liner seal were developed. A method is described for the high temperature flow conditioning of the GC injection port. In addition the new low bleed -MS bonded phase columns available from several manufacturers help reduct the noise level in the MSD. The combined improvements in the MSD and GC improved the overall MSD signal-to-noise level bewteen 5 to 10 fold. I am sure that there are more techniques and design changes that can be made to improve the performance in MSD's and other mass spectrometers. I seems that no matter what the level of sensitivity the mass spec spec was designed for, you can always use a little more sensitivity to detect that problem compound. I would like to hear from anyone who has any new tested or untested ideas or any other suggestion for improving the performance of the mass spectrometer. John J. Manura Scientific Instrument Services Supplier of Parts and Services for Mass Spectrometers and Other Scientific Instruments. Phone: (908) 788-5550 FAX: (908) 806-6631 e-Mail: sismspec@aol.com ****************************************************************************** From: vilboisf@iprolink.ch (Francis Vilbois) Subject: Re: peptides sequencing Date: Sat, 08 Jul 1995 23:55:07 +0100 Organization: Internet ProLink In article <3tm6ch$dhs@acmex.gatech.edu>, strecker@chemie.fu-berlin.de (Andreas Strecker) wrote: > There is also now the posiibility to sequence with MALDI-MS and > post-source-decay (PSD) technique. The first machines are already on the > market. The technique uses the "natural" fragmentation that occurs subsequent > to acceleration of the ions after MALDI. The fragments get a secondary > acceleration and are detectable as a fragmentation series of the original > molecule. This makes peptide sequencing possible. Major advantages: Little > sample amount required; low purity of sample required (peptide mixtures or > even complete digest probes are sequencable); ions differing in less than 50 > masses may be separated prior to sequencing within the MS by way of an > electronic switch. Major disadvantage: Only few machines installed yet (but > numbers are rapidly growing!) > > Andreas I have never seen any good data from these MALDI-MS PSD techniques. The mass spectrometers on the market are absolutely useless. Francis -- Francis Vilbois e-mail: vilboisf@iprolink.ch ****************************************************************************** From: topaz56@cyberg8t.com (BlueShift) Subject: MALDI-TOF Date: Sun, 9 Jul 1995 10:12:10 Organization: Cyberg8t Any MALDI gurus out there? BlueShift ****************************************************************************** From: db32@prism.gatech.edu (David E. Bostwick) Subject: Reception problems Date: 10 Jul 1995 10:16:03 -0400 Organization: Georgia Institute of Technology I have heard from a couple of people that all of the postings aren't making it to every site. There should be more than 90 postings by now. If you have not received all of the messages, let me know via e-mail, not a posting here. Send the mail to me at db32@prism.gatech.edu (a reply to this message should do that), to Sarah Shealy at ss17@prism.gatech.edu, or to the group contact address at mass.spec-request@chemistry.gatech.edu. -- David E. Bostwick Georgia Institute of Technology, Atlanta, GA, 30332 david.bostwick@chemistry.gatech.edu ****************************************************************************** From: Ashley McCormack Subject: Re: peptides sequencing Date: Mon, 10 Jul 1995 17:12:51 -0700 Organization: University of Washington Nntp-Posting-User: alm7203 In-Reply-To: <3tm6ch$dhs@acmex.gatech.edu> On 8 Jul 1995, Andreas Strecker wrote: > In article <3smd65$8bn@acmex.gatech.edu>, > depauw@gw.unipc.ulg.ac.be (De Pauw Edwin) wrote: > :Oligopeptides sequencing can be performed using liquid SIMS or > :electrospray ionization. If the interpretation of spectra of known > :compounds is easy, structure determination of unknowns is however > :not so direct. Fragmentation does not often give all the structural > :(Rest of post deleted) > > There is also now the posiibility to sequence with MALDI-MS and > post-source-decay (PSD) technique. The first machines are already on the > market. The technique uses the "natural" fragmentation that occurs subsequent > to acceleration of the ions after MALDI. The fragments get a secondary > acceleration and are detectable as a fragmentation series of the original > molecule. This makes peptide sequencing possible. Major advantages: Little > sample amount required; low purity of sample required (peptide mixtures or > even complete digest probes are sequencable); ions differing in less than 50 > masses may be separated prior to sequencing within the MS by way of an > electronic switch. Major disadvantage: Only few machines installed yet (but > numbers are rapidly growing!) > > Andreas > > While it is time consuming and sometimes difficult to sequence by MS/MS it is not impossible to sequence unknowns. Just look at the elegant work of Don Hunt's group in the last few years, sequencing MHC peptides using triple quadrupoles. While MALDI TOF instruments capable of PSD are a welcome addition to the techniques available, metastable fragmentation has been available to biological mass specrometrists for some years. It may produce different ion series that low- or high-energy CID but the ion series produced by those methods usually provide the information necessary to sequence peptides. And some peptides just won't fall apart the right way, no matter what you do to them. While I am a fanatical micro-LC/ESI/MS/MS triple quad user, IMHO whatever method works to get the answer is the one to use. Ashley L. McCormack UW Just my two cents, not my employers. ****************************************************************************** From: Ecuvac Subject: On-line catalogues ? Date: Tue, 11 Jul 1995 01:45:13 -0400 Organization: Vac Gen Any body know of any on-line catalogues I can browse ? Thanks Phil ****************************************************************************** Date: Tue, 11 Jul 1995 07:37:00 -0500 (CDT) From: "Steven P. Cepa 708-937-7539" Subject: Chicago area meeting PLEASE POST SORRY FOR THE LATE NOTICE. we'll need your help in getting good attendence MCM-MSDG Members Night Wednesday, July 19 Grand Palace Restaurant, Gurnee, IL Dale Scholler University of Chicago "Diet and Metabolism using Radioactive Tracers with MS" Robert Ludicky Morton International "Analysis of Polyesters and Other Polymers by LD-FTMS" Bryan Winger Extrel FTMS "Interfacing ESI with FTMS" Social hour @ 5:00 Dinner @ 6:00 choose chicken or vegetarian Talks @ 7:00 Cost $25 Call 708-245-3403 by July 17 to register. [Editorial comment: Dale Scholler is a recognized international expert on diet and food metabolism. His talk alone should be worth attending.] ****************************************************************************** Subject: Alternative Analytical Methods for ng/L Date: Mon, 10 Jul 1995 11:15:42 -0600 From: "David A. Bender, ECO contract person, Rapid City, SD " Organization: US Geological Survey The United States Geological Survey's National Water-Quality Assessment (NAWQA) Program's Volatile Organic Compounds (VOC) National Synthesis (VOC-NS) in conjunction with the USGS National Water-Quality Laboratory (NWQL) would like to request any information on ng/L (ppt) analytical methods for analysis of VOCs in ground water and surface water matrices. NAWQA's present VOC schedule has a reporting level of 0.2 ug/L. This reporting level is adequate for making observations about VOCs detected in ground water or surface water to federal regulatory standards or criteria. This reporting level, however, is not adequate for many other aspects of scientific investigations including for example characterization of the frequency of occurrence of contaminants, and understanding their transformation, transport, and fate. A reporting level of 1 - 10 ng/L is needed if quantitative assessments of VOCs in surface water are to be achieved. Currently the NWQL is using full scan purge and trap gas chromatography/mass spectrometry (P+T GC/MS), but by switching to selective ion monitoring a reporting level of 10 - 20 ng/L can be achieved. This latter method, however, does not allow for non-target VOCs to be identified and also only a select number of targets can be quantified. Because of these limitations the VOC-National Synthesis is compiling information on ng/L (ppt) analytical methods for VOC analysis in ground water and surface water matrices. The capabilities we seek include: 1. The ability to achieve 1 - 10 ng/L quantitatively; 2. The ability to detect non-target VOCs; and 3. A proven methodology in large-scale assessments (national, regional, or state monitoring programs). Any information would be greatly appreciated. A summary of received information will be posted. -------------------------------------------------------------------------- --- David A. Bender e-mail (605) 394-1780 x240 dabender@rc01dsdhrn.cr.usgs.gov -------------------------------------------------------------------------- --- ****************************************************************************** Date: Wed, 12 Jul 1995 15:55:57 +0000 (GMT) From: fan@pangea.usask.ca (Jhianzong Fan) Subject: Stability of ICPMS Organization: University of Saskatchewan Recently, I ran several batches of rock samples (sintered by sodium peroxide). The unstable signal of all standards on Zr, Hf kind of puzzled me. I selected three readings for each analyte. Zr (200 ppb, with ~120000 cps) in standard solution have RSTD ~10 to 15%, comparing to ~2 to 5% for other elements such as rare earth elements. Zr responses in sample solutions also have RSTD ~2 to 5%, which are normal. This phenomennon was not observed before. One obvious diference between sample solution and standard solution is that sample solution has higher TDS. The three readings of the standard solution is increasing, with maximum on the third reading, and it looks to me the correct one. Anyone on network has any idea to explain this phenomenon? ****************************************************************************** From: proulxp@ere.umontreal.ca (Proulx Pascal) Subject: Identifying doubly charge ions in ESI/MS/MS Organization: Universite de Montreal Date: Thu, 13 Jul 1995 00:45:45 GMT Hi, I am looking for suggestion for the identification of doubly charge ions in ESI/MS/MS of peptides. If the sampling of the m/z is fine, I can easily detect them by the isotope at M+0,5Da. But what if the spectrum has been acquired at low res? Any suggestions? Pascal Proulx PhD student Universite de Montreal proulxp@ere.umontreal.ca ****************************************************************************** From: greg@sciex.com (Greg King) Subject: Re: Stability of ICPMS Date: Thu, 13 Jul 1995 12:04:50 -0400 Organization: SCIEX In article <3u0vmb$h6e@acmex.gatech.edu>, fan@pangea.usask.ca (Jhianzong Fan) wrote: > Recently, I ran several batches of rock samples (sintered by sodium > peroxide). The unstable signal of all standards on Zr, Hf kind of puzzled > me. I selected three readings for each analyte. Zr (200 ppb, with ~120000 > cps) in standard solution have RSTD ~10 to 15%, comparing to ~2 to 5% for > other elements such as rare earth elements. Zr responses in sample solutions > also have RSTD ~2 to 5%, which are normal. This phenomennon was not > observed before. One obvious diference between sample solution and > standard solution is that sample solution has higher TDS. > The three readings of the standard solution is increasing, with maximum > on the third reading, and it looks to me the correct one. > Anyone on network has any idea to explain this phenomenon? I'm not even going to speculate on sources of signal fluctuation. Have you tried using an internal standard? Greg -- Greg King SCIEX 71 Four Valley Drive Concord, Ontario, Canada (905) 660-9005 greg@sciex.com ****************************************************************************** From: "Dr. S. K. Singhal" Subject: Question: Tandem MS of amino acids? Date: 14 Jul 1995 18:47:50 GMT Organization: The University of Western Ontario I am working on solving the structure of an unknown molecule using daughter ion analysis by ms/ms. I am using a Sciex API-III triple quadruple instrument with an ionspray interface, usually with an LC. I have one fragmentation pattern that I think may be consistent with glutamic acid. Does anyone know where I might find information on fragmentation of amino acids using tandem ms techniques? Please post your reply in this newsgroup or by E-mail to: ksinghal@mni.uwo.ca Thanks! ****************************************************************************** From: dhchace@acpub.duke.edu (Donald H. Chace) Subject: Re: Question: Tandem MS of amino acids? Date: 15 Jul 1995 02:10:58 GMT Organization: Duke University Medical Center In article <3u6iai$ipt@acmex.gatech.edu>, "Dr. S. K. Singhal" says: > >I am working on solving the structure of an unknown molecule using >daughter ion analysis by ms/ms. I am using a Sciex API-III triple >quadruple instrument with an ionspray interface, usually with an LC. > >I have one fragmentation pattern that I think may be consistent with >glutamic acid. Does anyone know where I might find information on >fragmentation of amino acids using tandem ms techniques? > >Please post your reply in this newsgroup or by E-mail to: > > ksinghal@mni.uwo.c > >Thanks! > > I have been working on the tandem mass spectrometry of amino acids for the past 3-4 years as part of our newborn screening R&D. A fragment that is observed arises as a result of a neutral loss of formic acid. Generally, much of our framentation data on amino acids are form butyl esters derivatives of amino acids in which a fragment is produced from the loss of butyl formate. These are neutral losses. ****************************************************************************** From: dhchace@acpub.duke.edu (Donald H. Chace) Subject: Re: Question: Tandem MS of amino acids? Date: 15 Jul 1995 02:16:25 GMT Organization: Duke University Medical Center In article <3u6iai$ipt@acmex.gatech.edu>, "Dr. S. K. Singhal" says: > >I am working on solving the structure of an unknown molecule using >daughter ion analysis by ms/ms. I am using a Sciex API-III triple >quadruple instrument with an ionspray interface, usually with an LC. > >I have one fragmentation pattern that I think may be consistent with >glutamic acid. Does anyone know where I might find information on >fragmentation of amino acids using tandem ms techniques? > >Please post your reply in this newsgroup or by E-mail to: > > ksinghal@mni.uwo.ca > >Thanks! > > >You should expect a neutral loss of COOH. I have fragmentation data from numerous amino acids (primarily butyl esters) that may be helpful to you. ****************************************************************************** From: Nahum Gat Subject: TechExpo WWW site for hi-tech users Date: 15 Jul 1995 19:13:29 GMT Organization: Opto-Knowledge Systems, Inc. Dear Colleague Please view the WWW site at: http://www.techexpo.com/ It is geared for hi-tech users and contains info on technical conferences, societies, magazines, and a directory of hi-tech companies, their products and services. TechExpo will post such info from qualified technical organizations. Regards, Nahum Gat, Ph.D. oksi@cerfnet.com ****************************************************************************** From: rdw@waikato.ac.nz Subject: Quantitative work with ESMS Date: 17 Jul 95 17:27:55 +1200 Organization: University of Waikato, Hamilton, New Zealand Hi, I'm one of a group of undergraduates looking at the quantitative abilities of our Universitys newly acquired Electrospray Mass Spectrometry device. We are tasked to look at anabolic steriods in this assignment, and to design and test a basic protocol to achieve the main goal. (ie to see whether this beast can do quantitative analysis, and tell us the concentr- ations of the standard steriod solutions we send thru it.) We would greatly appreaciate any wisdom you could pass on; things like experimental hints, good articles on the subject, fore warning of any pit falls etc this sort of thing would be really helpful to us. Tha