Flow Injection Spectrophotometric Determination of Hydrazine in Environmental Water Samples

A simple, accurate, sensitive and selective flow injection spectrophotometric method for rapid determination of amounts of hydrazine was proposed in this paper, which was based on p-dimethylamino-benzaldehyde (pDAB) reacts with hydrazine originating aldazine. The resulting yellow colored product is stable in acidic medium and has a maximum absorption at 460 nm. Upon the optimal condition, the absorption intensity linearly increased with the concentration of hydrazine in the range from 2.0–100.0μgL-1 and 100.0–1500.0μgL−1 with a correlation coefficient of R2 = 0.998(n=11) and and R2=0.9997(n=11), respectively. The experimental detection limit of 0.016μg L-1. The sampling frequency is 24 samples h-1 and the relative standard deviation was 0.38% for 0.1mg L-1. This method is suitable for automatic and continuous analysis, and successfully applied to determine the content of hydrazine in river water, pond water and waste water.