Determination of Carbophenothion and Dibrom Pesticides by Liquid Phase Lipase Enzyme by Voltammetric Methods

Liquid state lipase enzyme sensor was used for the detection of carbophenothionand dibrom organophosphorus pesticides and the electrochemical behavior of both thepesticides was studied. the developed enzymatic method is based on in situ generation ofp-nitrophenol by lipase enzymatic hydrolysis of p-nitrophenyl acetate substrate. theelectrochemically active p-nitrophenol gives an anodic oxidation peak potential at 0.05 v vs.sce. based on enzymatic inhibition property of carbophenothion and dibrom pesticides areselected for study of lipase enzyme inhibition. the current response is based on theproduction of p-nitrophenol under the influence of enzyme concentration, substrateconcentration, ph and time variation effects were studied. a linear calibration forcarbophenothion and dibrom was obtained in the various concentration ranges of 10-100ppb and 100-1000 ppb respectively with a correlation coefficient of 0.947 and 0.936 underthe optimized conditions by following the incubation time of 25 min. the electrochemicalexperiments were performed in 0.1 m phosphate buffer solution (ph 7.0) at roomtemperature. the limit of detection and limit of quantification values were found to be 37.40ppb, 124.6 ppb and 371.7 ppb, 1239 ppb for carbophenothion and dibrom respectively underoptimized conditions. the pesticide carbophenothion is more toxic than the dibrom asevidenced by the electrochemical studies. the developed liquid state lipase enzyme sensortakes less time for the analysis and no preconcentration extraction was needed for the study.