7/24/02
Avance500: ethylene glycol measuement says 301.2 degrees when edte
says 303K. bias = +1.8; SCH
repeat: ethylene glycol measurement says 301 degrees when edte says 303
K. bias = 1.8; SCH
Question:
Andy tells me that the lock signal drops some during long acquisitions (like hncacb) because of heating of the sample by the decoupling radiation. Presumably, that means that the differential between the true temperature and the edte reported temperature is different during experiments than during the ethylene glycol calibrations. So, I'd like to make an ethylene glycol sample with 5% D2O, and subject it to the hncacb pulse procedure. Should wait for the lock signal to drop some, then stop and immediately do the temperature calibration experiment to see the scale of this. Then again, I don't know if the presence of D2O will alter the temperature response properties of ethylene glycol. That could be checked by comparison to the 100% ethylene glycol sample.
Perhaps a simpler way is just to get an ordinary protein sample locked,
and then watch the lock level change when the temperature is altered to
see how much of a temperature change is indicated by a given decline in
lock signal.