Gas chromatographic determination of methoxyflurane in whole blood.

Sir,—It was interesting to read that Drs Jones, Molloy and Rosen used a similar injection technique to ours for analysis of volatile anaesthetics in whole blood (Brit. J. Anaesth. (1972), 44, 124). We have found pretreatment of blood samples to be unnecessary if glass liners are used in the injection port, columns are made of liquid methyl silicone (OV101) and the solid support is Chromosorb W or G. These columns allow clean separation of the water peak from methoxyflurane and all other volatile anaesthetic agents. Precision is +1.7 per cent and recovery from blood is 100 per cent. Analysis time is approximately 2 minutes, samples may be as small as 50 /*1. and minimal labour is involved (Cousins and Mazze, 1972).