EVALUATION OF ALTERNATE COUPLING REAGENTS TO REPLACE ALPHA-NAPHTHYL AMINE FOR DETECTION OF NITRATE REDUCTION

Abstract

Four naphthyl compounds, N,N,dimethyl-1-naphthylamine, N-1-naphthyl-ethylene-diamine dihydrochloride, 8-amino-1-naphthol-5-sulphonic acid and 1-dimethylamino sulphonic acid, were evaluated as replacements for .alpha.-naphthyl amine [which is a potential human carcinogen] in the bacteriological nitrate reduction test. These compounds were observed for their ability to detect standardized nitrite concentrations and nitrate reduction in 8 bacterial cultures. The results indicated N,N,dimethyl-1-naphthylamine and N-1-naphthyl-ethylene-diamine dihydrochloride, at concentations of 0.035 M, were satisfactory alternatives. The working concentration of the latter might be reduced, as indicated by the results of sensitivity tests.