Scheduling
The instruments are
divided into two scheduling groups:
(1) The DRX 500, AMX
400, Mercury 400 and Mercury 300 are available to all individuals who have been
trained. Access is first-come, first-served on a weekly, internet access time
sheet:
Internet Scheduling for DRX 500, AMX
400, Mercury 400 and Mercury 300
(2) Time on the DSX 400
and DSX 300 is coordinated by Dr.
Leisen. Measuring times need to be requested before Friday noon to be
considered for the following week.
The Center Manager
reserves time for user training, instrument maintenance, and operator-acquired
spectra. One work station exists in the Center for dedicated offline data
processing.
Instrument Availability
Varian Mercury 400
and Varian Mercury 300
These instruments are
available to all trained users on a first-come first-use sign-up. Do to the
high demand for this instrument the following sign-up rules are in force.
Between 8:00 AM and
Between
From 10:00 PM until
8:00 AM and all weekend one can sign up for an unlimited amount of time.
The time between 11:00
AM and 1:00 PM Monday through Friday cannot be reserved. This time is available
for single proton spectra on a first-come first-served basis. If no one is
waiting to use the instrument more spectra can be run. However, if someone
should show up you must give up the instrument and get to the end of the line.
Bruker Instruments
The Bruker instruments can be reserved by any trained user for any length of time during a one week period.
Preparation of Solution Samples
The only way to obtain
useful data is to have well prepared samples.
Samples of the required
material should be dissolved in an appropriate DEUTERATED solvent. The deuterated solvent serves two purposes. First it acts as
the lock material and secondly, if you are running a proton spectrum, it
prevents the presents of a large solvent peak.
Use an appropriate
concentration.
For a proton spectrum
on the majority of organic materials of molecular weight of under
500 one needs between 3 mg to 5 mg dissolved in 0.7 ml of deuterated
solvent. Since 13C is of lower natural abundance and lower sensitivity
one needs more material to be able to obtain data in a reasonable amount of
time. In this case one should use a minimum of 25 mg dissolved in 0.7 ml of deuterated solvent.
Solutions samples should be just that, solutions. There should be no particulate matter in the NMR tube. If necessary filter your samples. Gel like samples will be difficult to shim and give very broad lines.