ANALYTICAL APPLICATIONS OF PHOSPHATASE ENZYME SYSTEM - DETERMINATION OF BISMUTH BERYLLIUM AND PESTICIDES

A fluorimetric method is described for the determination of bismuth and beryllium, and the pesticides methyl parathion, Aldrin and Heptachlor. The procedure is based on the inhibition of acid and alkaline phosphatase by these substances. The substrate umbelliferone phosphate is used, which is cleaved by phosphatase to the highly fluorescent umbelliferone (λex=346 nm at pH 5, and λex=365 nm at pH 8; λem=450 mm). Beryllium (0.01-0.30 μg/ml), bismuth (1-70 μg/ml), Aldrin (5-100 μg/ ml) and Heptachlor (50-700 μg/ml) inhibit the hydrolysis catalyzed by alkaline phosphatase, and methyl parathion (5-500 μg/ml) that catalyzed by acid phosphatase, causing a decrease in the slopes of the fluorescence-time curves. This decrease is a direct measure of the concentration of inhibitor. 4-Methylumbelliferone nonanoate was found to be a good substrate for acid phosphatase in the presence of large amounts of phosphate (1.0 M). As little as 0.00006 units of acid phosphatase can be assayed with an accuracy and precision of 2%. © 1969.