NMR Lab. Humidity, Temperatur |
The site requirement for NMR instruments
| Mode | Temperature oC | Temperature oF | Relative Humidity (RH%) |
|---|---|---|---|
| Operational | 17-24 |
60-75 |
20%-80% |
| Optimum | 20 |
68 |
40%-60% |
| Stability | +/- 1.0 |
+/-1.8 |
+/-10% |
| Non-operational | below 17 or above 24 |
below 60 or above 75 |
below 20% or above 80% |
| System | Pressure(psig/kpa) | Flow Rate(LPM/SCFH) | Dew Point |
|---|---|---|---|
| 200 - 400 MHz | 35 |
45 |
-40C |
| 500 and 600 MHz | 45 |
48 |
-40C |
| Solid State NMR | 90 |
80 |
-40C |
Reference: Varian Installation Planning Guide
Non-operational mode----- Shutdown the instrument!
For optimal performance, the temperature around the superconduct magnet should not very. The temperature stability around the magnet will affact the homogeneity of the magnet ---- Shimming and lock. Few tenth of degree change in the probe, will affact the quality of water suppression experiment and NOESY.
High humidity will affact the probe operation in the solid state NMR ----- Arcing
The house compressed air supply must provide a source of air that is clean, dry and free of contaminats, with a dew point -40 C minimum.
RH% caculator: http://einstein.atmos.colostate.edu/~mcnoldy/Humidity.html
Input the temperature of air supply, and relative humidity reading from the meter, the dew point could be calculated.
For example: the temperature is 22C and RH reading is 50%, then dew point is - 43.20C
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RH% is used to describe the amount of water vapor that exists in a gaseous mixture of air and water. The relative humidity defined as the ratio of the partial pressure of water vapor in the mixture to the saturated vapor pressure of water at the defined temperature. Relative humidity is normally expressed as a percentage and is defined in the following manner: RH= (Pwater)/(Psaturated) *100% where: RH% is the relative humidity of the mixture being considered; Pwater is the partial pressure of water vapor in the mixture; and Psaturated is the saturated vapor pressure of water at the temperature of the mixture. Good Resources for Temperature and Humidity Control: http://www.newportus.com/Products/Humidity/index.htm
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