Chromatographic Techniques for the Analysis of Organophosphate Pesticides with their Extraction Approach: A Review (2015-2020)

In agriculture, a wide range of OPPs have been employed to boost crop yield, quality, and storage life. However, due to the ever-increasing population and rapid urbanization, pesticide use has...

Effects of Organophosphorus and Pyrethroid Pesticides on Antioxidant Enzymes and Reactivation Effects of Pralidoxime: In vitro Studies

The present study was aimed to assess the inhibition effects of organophosphate pesticides, malathionR, dichlorvosR; pyrethroid pesticides, deltamethrinR, λ-cyhalothrinR on antioxidantenzymes and reactivation ability of pralidoxime against pesticide inhibited-antioxidant enzymes. Oximes were reported by reactivation ability against organophosphate inhibited- acetylcholinesterase and we focused to investigate the reactivation effect of pralidoxime against organophosphate inhibited–antioxidant enzymes. IC50 values were determined by means of activity percentage diagrams. The concentrations of deltamethrinR, malathionR,dichlorvosR, λ-cyhalothrinR that inhibited 50% of catalase were 5.2 μM, 158 μM, 133 μM,320 μM, respectively, inhibited 50% of superoxide dismutase were 62 μM, 240 μM, 328 μM, 2320 μM, respectively and inhibited 50% of glutathione peroxidase were 0.7 μM, 1198 μM, 1638 μM, 98 μM, respectively. All pesticide doses showed inhibition effect on antioxidant enzymes. DeltamethrinR was found to be a more potent inhibitor for the antioxidant enzymesfollowed by the rest of pesticides used in this study. Reactivation effect of pralidoxime was determined for organophosphate inhibited-enzymes. Reactivation results showed that only catalase is reactivated by pralidoxime against dichlorvosR and malathionR. Under the exposureof 50-800 μM malathionR concentrations, catalase activity % was calculated as 72-11%,respectively. After inhibited catalase by malathionR incubated with 1 mM and 10 mMpralidoxime, catalase activity % was calculated as 92-31% and 98-39%, respectively. Under the exposure of 100-1500 μM dichlorvosR concentrations, catalase activity % was calculatedas 50-6%, respectively. After inhibited catalase by dichlorvosR incubated with 1 mM and 10mM pralidoxime, catalase activity % was calculated as 95-30% and 93-28%, respectively. When the results are examined, it is seen that increasing the pralidoxime concentration does not significantly affect the reactivation percentage of the catalase enzyme.

A simple paper-based biosensor for on-site visual detection of organophosphate residues

In general, the laboratory method of analyzing pesticides in vegetables is complicated due to the high cost of equipment and chemicals. The process of analyzing pesticide residues generally requires expertise as well as a significant period of time. In this study, a paper-based biosensor was developed for the detection of acetylcholinesterase (AChE) inhibitors, particularly organophosphate pesticides. The paperbased biosensor was constructed based on the Ellman colorimetric assay by immobilizing AChE on cellulose paper with 2% alginate gel, 0.25% glutaraldehyde and the colorimetric reagent 5,5-dithio-bis-(2-nitrobenzoic acid) (DTNB) in phosphate buffer (pH 8.0). As a substrate, acetylthiocholine chloride (ATChCl) was used. The results showed that the developed paperbased biosensor has been stable for 2 weeks with a detection limit of 0.03 mM of chlorpyrifos. The paper-based biosensor was applied to detect organophosphate pesticides in vegetables from the farmers’ market, Ratchaburi Province. It was found that the test results of the paper-based biosensor were similar to the commercial GT-test kit. The paper-based biosensor was 10 times faster than the GT-test kit in terms of testing time and the results were easy to identify due to the color-based indicator. As a result, a paper-based biosensor is rapid, portable and easy to use by the general population.