采用水杨醛处理试液、双指示剂指示终点的双指示剂中和法测定强酸中的肼 .该法能排除强酸的干扰 ,简单快速 ,相对标准偏差为 1 .2 1 % ( n=6) ,加标回收率为 98.7%— 99.1 % .用于测定硫酸肼生产过程中结晶母液中肼的含量 ,结果满意 . The salicylaldehyde treatment solution was used as a double indicator reagent to indicate the end point of the double indicator neutralization method for the determination of hydrazine in strong acids.The method can eliminate the interference of strong acids and is simple and fast with a relative standard deviation of 1.2% ), And the recoveries were 98.7% -99.1% .The results were satisfactory for the determination of hydrazine in the crystallization mother liquor during the production of hydrazine sulfate.