Simultaneous determination of hydroxylamine and cyanide in formulations containing pralidoxime salts by flow injection.

A flow injection method is described for the simultaneous determination of cyanide and hydroxylamine which are known decomposition products of formulations containing pralidoxime salts used in the treatment of anticholinesterase poisoning. By using the diffusion of HCN from the carrier stream followed by amperometric detection, high selectivity and sensitivity and a wide dynamic range can be achieved. Hydroxylamine is determined by its oxidation with iodine to nitrite which can then be determined colorimetrically. The gas diffusion unit effectively acts as a stream splitter for the two analytes allowing their simultaneous determination from a single sample injection. The performance of the system and its applicability to thermally stressed pralidoxime solutions are described.