Optical biosensor for simultaneous detection of captan and organophosphorus compounds

The optical biosensor consisting of GST and acetylcholinesterase (AChE)-immobilized gel film was developed to detect captan and organophosphorus compounds simultaneously in contaminated water. The sensing scheme was based on the measurement of decrease of products formation (s-(2,4-dinitrobenzene) glutathione and alpha-naphthol by GST and AChE, respectively) due to the inhibition by captan and organophosphorus compounds. The absorbance of s-(2,4-dinitrobenzene) glutathione and alpha-naphthol was detected at 400 and 500 nm, respectively, by a proposed optical biosensor system. It was observed that AChE was inhibited by both captan and organophosphorus compounds, and GST was inhibited only by captan. The simultaneous detection and quantification of captan and organophosphorus compounds could be successfully achieved by the proposed sensor system. The proposed biosensor could successfully detect the captan and organophosphorus compounds concentration from 0 to 2 ppm.