Question

9.(or) 13. Which of the following conditions would be desirable ?

(a) more sample - measurement on a lower MHz spectrometer

(b) less sample - use of a higher MHz NMR spectrometer. [3marks]

The question is from structural biology(NMR Spectroscopy).

Answer 1

The desirable condition will be:

(a) more sample - measurement on a lower MHz spectrometer.

Reason: If amount of sample is less, then there is high chance of impurities in the NMR sample which may contribute to peaks in the final spectra. High frequency NMR will give enhance the splitting of peaks arising die to impurities along with the sample. But when sample amount is high, there will be less impurities contributing to the spectra recording on low frequency NMR. In addition, high frequency NMR (e.g., 800 MHz) availability in usual laboratory is scarce, however low frequency NMR (300 MHz) are readily available.