This is how to change the sample temperature using 'EDTE'. All the spectrometers are normally set to 298 Kelvin.
Please ask for help if you are having problems with this method. If you plan to go above 100C you might want to ask me to sit in and help.
The low temperature 278-298K is done in the exact same fashion as described below and no additional changes are necessary.
For studies below 278K go ahead and contact us as we need to use N2(g) boiloff to attain such values.
USE THE WHITE CERAMIC SPINNERS FOR VARIABLE TEMPERATURE WORK. THE BLUE ONES WILL MELT. The Ceramic spinners are located in the blue box in the cabinets
*you should only increment the temperature in 20-30 Kelvin steps. Don't go too fast as it can crack the glassware.
**also, stay at least minus 10K below the solvents boiling temperature.
**DO NOT SPIN.
- coiltemp - '120s' is ok for question. now in bottom left corner a value for coiltemp should show. this is the value of the temperature at the shims and is different from the value you want to set (eg 120C). IF COIL TEMP IS ABOVE 80C OR BELOW 5C THEN STOP AND LOWER OR RAISE THE SET TEMPERATURE (BELOW). This is just a safety to monitor the surrounding temperatures in the magnet and again is different than below (the real temperature at the sample)
- edte - edit temperature module is launched (below)
- in GREEN is the real sample temperature. Click "Change" button in "Target temp" and plug in your value
- be sure the "Probe Heater is "On"
- "Probe Heater" is the maximum heating power. OK to change to a higher value such as 50% (it is somewhat arbitrary).
- The GREEN actual temperature should start to ramp up now..
- If it doesn't reach its target value within 5 minutes try increasing the "Gas Flow" by clicking the "+" button. I wouldn't go over 800 Li/Hour however
- If it still doesn't reach its target then increase "Probe Heater" percent even higher
- If you are acquiring 13C or 2D NMR you might need to tune the probe as the temperature effects it quite a bit
- Don't eject sample until you've finished below
- "Target Temp" to 298K
- "Probe heater" to 4 %
- "Flow Rate" to 270 l/h
- wait until "Sample temp." is below 310K before ejecting.
- once it is there you can put the standard CDCl3 back in using blue spinner and return the ceramic to its case
- typically our NMR's are within +/- 2K to the real temperature in the range 285-310K
- as you move away from these settings the actual/real temperature drifts
- calibrating real temperatures is quite easy using 1D 1H NMR of Methanol or Ethylene Glycol
- we have these samples and ask if you can't find them in the NMR lab
- here is a link below and the references
Temperature_calibration