The micro determination of cyanide: its application to the analysis of whole blood

Abstract

An introduction to the existing methods for the analysis of cyanide is given and some of the limitations to the methods are pointed out.

A modification of the Epstein method is described, in which Cavett blood-alcohol flasks are used. This method can be applied to small samples of 2 ml volume containing 0·2 µg of cyanide. By strict control of the conditions it is shown that a high degree of accuracy can be achieved. Interference by heavy metal ions is avoided by using 2 mg of the disodium salt of EDTA per ml of blood. It is therefore suggested that this anti-coagulant should be used when the blood is collected. Experiments on the partition of cyanide in whole blood showed that 5 minutes' exposure resulted in more than 70 per cent. of cyanide being bound to haemoglobin. This value remained unchanged in the presence of a transport inhibitor.