****************************************************************************** From: Werner Spahl Date: Mon, 16 Feb 1998 13:35:09 +0100 Subject: References for negative ESI-HR? Organization: [posted via] Leibniz-Rechenzentrum, Muenchen (Germany) Hi, I'm looking for reference substanzes for negative ESI-HR. Chapman (Practical Organic Mass Spectrometry) mentiones PEG or PPG Sulfates but I can't find them in any chemical catalog. Where can I buy them or can they be made out of the appropriate PEGs or PPGs in a simple way? Werner Spahl (ui22273@sun1.lrz-muenchen.de) "The meaning of my life is to make me crazy!" ****************************************************************************** From: "Pedro Domingues" Date: Mon, 16 Feb 1998 17:11:50 +0100 Subject: Re: References for negative ESI-HR? Organization: Universidade de Aveiro, Portugal Hi You can find several PEG's (Polyethylene glycol) on Sigma or BDH catalog. Al you have to do is choose one that has a average molecular wt. near the mass of your substance. You should have great care with contamination's: - Use the small concentrations of PEG (less than 50 ng/microliter) - Reserve seringes and other material for PEG - Beware with problems due to the contamination of the source, loops etc. We usually aquire first the sample spectra and, only after, do the calibration Hope this helps Pedro Domingues Chemistry Dpt. Aveiro University Portugal ****************************************************************************** From: cody@jeol.com (Chip Cody) Subject: Re: References for negative ESI-HR? Date: Tue, 17 Feb 1998 15:12:05 GMT Organization: JEOL USA, Inc. We used PEG sulfates for negative-ion high-resolution ESI measurements (Cody et. al. Anal. Chem. 1992, 64, 1561-1569), following the report by Mark Hemling of the use of these compounds for negative-ion FAB. The synthesis of these compounds was reported in Mark's ASMS abstract See Hemling, M. "Negative Ion FABMS Reference Compounds", Proc. of the 38th ASMS Conference on Mass Spectrometry and Allied Topics, Tucson, AZ, June 3-8, 1990. Or...you can obtain some Ivory dishwashing soap. That is a mixture of polyether sulfates. Use the old, milky white liquid and not the new clear liquid. You will see reference masses from about 200 u to up to at least 1000 u. I don't believe that I've posted the masses on our web page, but I'll try to do that some time in the near future. Good luck! -- "For purposes of ... New Jersey Right to Know Act. Contents partially unknown." |____________ |_ Robert B. Cody, Ph.D |________________________________ Product Development Manager |__ Mass Spectrometry |________________________ JEOL USA, Inc. |_ http://www.jeol.com |__________ e-mail: cody@nojunkmail.jeol.com |_ (REMOVE 'nojunkmail' TO REPLY) ============== Do not send me spam or advertising via e-mail !! =========