I just thought that I would like to add my two cents worth to this discussion.
I don't think that good user training necessarily means that we have we have to
operate our spectrometers the way we did 10 or 15 years ago. As software, hardware
and NMR experiments (pulse sequences) have become increasingly more complex, the
manufacturers have dove a very good job of creating safe, reliable, user-friendly
automation that makes NMR accessible to more students, and at the same time increases
lab efficiency. The student, at least at the early stages of NMR operation, does not need
to know how to manually lock or shim, or type 40 character command lines in order to
obtain basic proton, carbon, DEPT, COSY or HSQC spectra.
Here is the way that NMR training for organic chemistry students is handled here, and it
seems to work:
1. The students are first exposed to NMR in second their year organic courses. These classes
are huge (full of wannabe MDs) so we do not have the luxury of providing hands-on NMR for
these students. The emphasis here is on interpretation of basic proton and carbon spectra.
2. In third year, the students are required to run at least proton and carbon spectra on their
products. To do this, they use an Avance 300 running IconNMR. This is an extremely
reliable hardware/software combination, and provides good reliable spectra for months on end
without me have to do anything other than fill cryogens and clean up disk space. The formal
training that they receive is progressive and consists of:
- Safety and good laboratory practice in the NMR laboratory. A hand-out (which I can
share with the group) is provided.
- Proper sample preparation - Strongly emphasized, VERY IMPORTANT. Again, a written
hand-out is provided.
- Basic operation of IconNMR with a "hand-waving" if occasionally somewhat erroneous
(I scream at the mention of "radio waves") description of how an NMR works.
- Spectral interpretation. Although the spectrometer spits out a basic plot of their spectrum,
the
students down load their data to open area computers or their own personal computers for
off-line processing and analysis. There are a number of inexpensive or even free software
options here. It would be shameless self-promotion to say what our students actually use.
In order to assist with this, I maintain my "office" in the NMR lab close to the spectrometers.
This is not so much to prevent the students from making mistakes, but to serve as a resource for
the students. I often look at their spectra, and give them suggestions on experiments that they
can use to solve a particular chemical problem, or identify what went wrong in a given
experiment. With decent sample size, a student can obtain proton, carbon, COSY and possibly
HSQC spectra in a 1/2 hour time slot.
3. The students that are likely to go on to graduate school or into industry as bench chemists often
do
summer or 4th year research projects. Although IconNMR still handles the bulk of routine
work, the students are trained in how to adjust or optimize parameters, and how to run the
spectrometer manually for experiments such as GOESY. The 300 has an extremely fast autolock
which sets all of the proper parameters for the solvent and probe. Gradient shimming is
used for essentially all samples. However, I do explain to the students what the gradient shimming
is
doing, and what the field profile means. By this point the students are comfortable with the lab
policies and procedures, and produce good spectra from the majority of samples.
If they use the older spectrometer (AMX 500) they are taught how to manually lock,
shim and tune the probe.
One of most important skills that students can learn at this point is how to have a critical look at
the basic spectra, and then select the PROPER experiment to solve the problem at hand.
4. In forth year, some students take a course called "Advanced Chemical Techniques" where I do
most of the NMR section. Here, I give them an introduction to the NMR Hamiltonian, a derivation of
the
rotating frame vector model of NMR, the origins of shifts and couplings, INEPT and INEPT, NOE,
and the introduction of an evolution time and the second dimension. They are given discussions of
COSY, HSQC, HMBC, NOESY, ROESY and several other 2D techniques, with a bit about how they
work and when they should be used. They are then given a relatively complex organic unknown (15 to
25
carbons) and are expected to select and run NMR experiments and determine the structure, including
relative stereochemistry, if possible. They are strongly encouraged to not simply check off every
2D
experiment in the menu, but to think of possible structures and select experiments wisely.
This handles the training for the bulk of our users who are organic chemists who think of NMR
primarily
as a tool. It also parallels closely the way NMR is used by organic chemists in industry. We find
that
even organic graduate students who are very competent at running the spectrometers manually, use
automation for the bulk of their samples. The spectra produced are just as good, and it frees their
time
for other things.
Students whose primary interest is NMR spectroscopy, especially solid-state NMR and biochemical
NMR, receive far more hands-on but narrowly focussed NMR training.
Cheers
-Kirk
Kirk Marat, Ph. D., NMR Facility Manager
Dept. of Chemistry
University of Manitoba
Winnipeg, MB, R3T 2N2, CANADA
ph. (204) 474-6259 FAX: (204) 474-7608
kirk_marat_at_umanitoba.ca
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Received on Thu Apr 13 2006 - 16:07:57 MST