UW CHEMISTRY NMR

We had several requests to explore increasing the high temperature limit on the instrument.  This needed rather careful testing, without which we could precipitate a catastrophic quench of the magnet.  On the AV500 system, such a test was completed recently.  We have concluded that, for experiments that need to run for more than a few hours, a maximum sample temperature of +70 C is allowable.  This temperature can be maintained without affecting the magnet system, using an active cooling of the magnet bore.  A temporary but usable jig is already in place to achieve this.  The absolute maximum mentioned for the probe and shim stack by Bruker is +80 C for short term experiments only (a maximum of 1 hour).  If there is a need for reaching temperatures between +70 C and +80 C, you should take the active help of facility staff so that the system can be monitored while the experiment is underway at these temperatures.

Tests are in progress on other relevant systems to determine the maximum VT limit. You will be alerted about the results of the same in due course.