UW CHEMISTRY NMR

Dear Users

The NMR instruments in our facility are not only expensive but they are result of years of  extensive R&D and exquisite engineering.   They are robust enough to tolerate quite a bit of abuse.

But, there are limits to how much these versatile and delicate instrumentation can take and still keep functioning.

These days by automation, all the way from ATMA probes to sample queueing with robots and smart software, we have almost eliminated the case of ‘user neglect or ignorance’  that can damage instrument hardware.

But, there is one area that is still the sole responsibility of the userbase, which the folks who run the facility cannot control i.e.  your NMR sample preparation.   There are limits that need to be respected with the following parameters, that are intertwined with your NMR samples. Please take a moment to reflect on the quetions in italics below :

• Sample Temperature limits : will the magnet be harmed at the temperature and duration at which I collect data ?
• Behavior of samples as a function of temperature : will it freeze or boil at the temperatures I reach ?  Will that lead to sample breakage ?
• Sample Ionic Concentrations : is it going to lead to sample RF heating ? is  it going to cause irreversible damage to the NMR probehead ?
• Kind of solvents you use to dissolve your NMR samples : will there be unexpected phase changes as a function of time or temperature ? What will that do to the integrity of the NMR sample and tube ?
• Suitability of the experiment you are attempting vis-a-vis the nature of your NMR sample : is it going to overload the RF system and potentially damage the instrument ? Am I using an optimized parameter set to avoid that ?
• NMR sample tube considerations :  is it a thick (enough) walled tube, if I am attempting an observation under high pressure inert atmosphere to prevent oxidation or line broadening ?  if I am trying to maximize concentration with a thin walled tube,  is it prone to breakage ? can I think of alternatives like coaxial capillary insert tubes for the purpose ?

There are always creative alternatives to achieving your final goal without causing lasting harm to the instruments.  But, it is an important first step for you to think about these before you submit your sample.  When in doubt, please reach out to one of us for guidance.  

Thank you for your co-operation.

NMR FACILITY

4/1/2025