A radiochemical method for determining cyanides in solution

Abstract

Between 17 nmol and 400 µmol of a cyanide (0·5 µg to 10 mg of Cyanide ion) can be determined in aqueous solution by passing the solution through a column of silver iodide labelled with silver-110m and counting the filtrate. Two moles of cyanide are required to dissolve each mole of silver. The method is rapid, sensitive and precise and does not require the use of expensive counting equipment. Little or no interference has been detected from 0·1 M nitric, hydrochloric and sulphuric acids, from 0·1 M solutions of the chlorides of sodium, potassium, magnesium and calcium, or from 0·1 M solutions of ammonia, potassium hexacyanoferrate(III), potassium hexacyanoferrate(II) and potassium thiocyanate. Sodium thiosulphate has been shown to interfere.