University of Colorado at Boulder NMR Facility
Department of Chemistry and Biochemistry
Temperature Calibration for
VT NMR Experiments
When you perform a Variable Temperature (VT) NMR experiment, the displayed
temperature is not necessarily the actual sample temperature. When
you need to know the actual temperature, with a high degree of accuracy,
it is important to calibrate the sample temperature, relative to the displayed
The common method to perform this calibration is to observe the chemical-shift
separation between the OH resonances and CHn resonances in either Methanol
or Ethylene Glycol (generally Methanol is used for low-temperature calibration,
and Ethylene Glycol is used for temperatures above ambient). The
temperature dependence of this shift has been well-studied, and a variety
of conversion methods have been reported to enable the determination of
Below, there is a link to a Microsoft Excel(r) spreadsheet (.xls file),
which allows easy determination of either (a) temperature from measured
shift separation, or (b) predicition of peak shifts for a particular temperature.
In addition, a calibration was performed by me at the University of Nebraska
for Deuterium NMR, when the 2H signal from d4-Methanol is observed (the
isotope dependence is significant).
The use of this spreadsheet is simple. There are fields to enter
temperature (calculating the chemical shift separation), and fields to
enter peak-separation (calculating the temperature). A variety of
solvent systems are included.
Calibration Calculator>> Right-Click
the link to save the spreadsheet on your computer. This was created by Rich Shoemaker at the University of Nebraska Lincoln.