Abstract

A flow injection analysis coupled with catalytic spectrophotometry is proposed for simple and rapid determination of trace hyamine cationic surfactants (CSs) in tannery effluent and environmental water. The scheme is based on the markedly catalytic reaction of cationic surfactants, i.e., cetyltrimethylammonium bromide (CTMAB) and cetylpyridinium bromide (CPB) which, on oxidation using KIO4 in highly acidic hydrochloric acid medium discolour Arsenazo(III). Under the optimum conditions, the linear ranges for CTMAB and CPB are 0.1-20mg l-1, and all relative coefficients of the two CSs in different subsections of the linear ranges exceeds 0.9986 (n = 11). The detection limits (3δ) of both the CSs are 0.08mg l-1, and the recoveries range from 95.7% to 103.1%.

The relative standard deviation (R. S. D.) is 1.21% for 2mg l-1 CTMAB standard solution (n = 21). The developed method, which is suitable for automatic and continuous analysis, can monitor 15 samples per hour. It has been applied successfully to tannery effluent and environmental water samples.