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Chemical shifts for the aromatic tritons of toluene decrease in the order meta>para>ortho for pure toluene, but in the order meta>ortho>para for dilute solutions of toluene in carbon tetrachloride, chloroform, cyclohexane and dimethyl sulphoxide; m-xylene shifts are 5>4,6>2 in the pure state and 5>2>4,6 in carbon tetrachloride and dimethyl sulphoxide; o-xylene shifts are 4,5>3,6 in the pure state and reversed in carbon tetrachloride.

Tritium labelled hexamethyldisiloxane is a suitable material for the internal referencing of 3H NMR spectra. Such a referencing procedure is necessary where the instrument is not capable of scanning 1H resonance under identical experimental conditions. Hexamethyldisiloxane may be tritiated to high activity (typically 1 Ci ml−1) by Raney nickel catalysed exchange with elemental tritium in a simple one-step procedure. A variety of heterogeneous catalysts are shown to be inactive in the common labelling method involving exchange with tritiated water.

Chemical shifts for tritons in chlorobenzene have been measured in the pure compound and in a dilute solution in cyclohexane using a 64 MHz NMR spectrometer. The order of shifts is o>m>p. Triton shifts in pure bromobenzene, fluorobenzene and toluene have also been measured and the influence of CCl4 solvent on the aromatic triton shifts in toluene explored. Complete resolution of the three aromatic triton positions is achieved in pure toluene, but the ortho and para shifts are not resolved in 25% solution in CCl4.