The water,dimethylamine and formaldehyde dimethylhydrazone in unsymmetrical dimethylhydrazine were determined by capillary gas chromatographic method with benzene as internal standard.The results showed that good separation effect was obtained with the capillary column SE-54 and weakness of trace impouring imprecisely was avoided by the internal standard method.The method has broad linear scope and the correlation coefficient for water,dimethylamine and formaldehyde dimethylhydrazone is 0.9987,0.9993 and 0.9986 respectively,all approaching 1.The recoveries for water,dimethylamine and formaldehyde dimethylhydrazone in sample are 99.4%,101%and 99.7% separately.In addition,this method had high accuracy and good repetability.
