The determination of hydrazine and 1,1-dimethylhydrazine,separately or in mixtures,by high-pressure liquid chromatography

A rapid, sensitive liquid chromatographic method for the determination of hydrazine and 1,1-dimethylhydrazine, separately or in mixtures of varying proportions, is described. The procedure involves salicylaldehyde derivative formation followed by chromatography on a reversed phase (octadecylsilane) column with acetonitrile (52%)—0.14 M potassium dihydrogenphosphate (48%) as a mobile phase and u.v. (254 nm) detection. This system is sensitive to 2 μg ml^-1 of hydrazine and 5 μg ml^-1 of 1,1-dimethylhydrazine and has a relative standard deviation of less than 1%. Monomethylhydrazine forms an unstable salicylaldehyde hydrazone; although it cannot be determined, it can be detected (sensitivity 5 μg ml^-1 ) and does not interfere with quantitative measurement of either hydrazine or 1,1-dimethylhydrazine.