1. Purpose

This experiment demonstrates the technique used to observe deuterium (²H, I = 1) by NMR spectroscopy in natural abundance (0.015%). As an example we have chosen pure ethanol, since this method is currently routinely used in food analysis. Since the isotope distribution in ethanol is dependent on the sugar source and its geographic origin, quantitative ²H NMR spectroscopy can be used to detect fraud [3, 4].

2. Literature

C. Brevard, J. P. Kintzinger, in: NMR and the Periodic Table, R. K. Harris, B. E. Mann (eds.), Academic Press, London, 1978, 107–128.
J. W. Akitt, in: Multinuclear NMR, J. Mason (ed.), Plenum Press, New York, 1987, 171–187.
M. L. Martin, G. J. Martin, NMR–Basic Principles and Progress 1991, 23, 1–62.
G. J. Martin, M. L. Martin, Annu. Rep. NMR Spectrosc. 1995, 31, 81–104.

3. Pulse Scheme and Phase Cycle

Proton-decoupled deuterium pulse sequence and phase cycle

4. Practical Procedure

Time requirement: 30 min

Sample: pure ethanol.

A multinuclear probe-head is required for the measurement of ²H spectra. Disconnect the ²H lock channel and remove any ²H-stop filter from the transmitter line (which is sometimes hidden in the preamplifier). Use an ¹⁹F lock, if available; alternatively the