Highly sensitive reaction of nitrate with brucine and 3-methyl-2-benzothiazolinone hydrazone hydrochloride for the determination of nitrate in environmental samples.

A modified and highly sensitive spectrophotometric method for the determination of nitrate in trace quantities in environmental samples is described. The method is based on the reaction of nitrate ion with brucine and 3-methyl-2-benzothiazolinone hydrazone hydrochloride (MBTH) in sulfuric acid medium to yield a violet-colored product which is stable for over two days. The optimum photometric range for the determination of nitrate is 0.04-0.16 microg cm(-3) and the Sandell's sensitivity being 0.000279 microg cm(-2). The proposed method is applied to various water samples and the results indicate that the reaction is highly sensitive than the original brucine method.