Chemometrics Assisted QuEChERS Extraction Method for the Residual Analysis of Organophosphate Insecticides: Application to Their Dissipation Kinetics in Open Field Ecosystem

Abstract

The present study aimed to investigate the dissipation kinetics and residual levels of five organophosphate pesticides in a carrot- and potato-field ecosystem by sensitive and selective liquid chromatography-tandem mass spectrometry method. The optimization of the modified QuEChERS extraction method was carried out using the cost-effective chemometric tool equipped with Plackett-Burman and central composite designs. Based on the response surface methodology the optimized conditions were found to be 56.5 mg of primary secondary amine sorbent, 1.53 g of sodium chloride, and 213 mg of C18. The average recoveries of the method were obtained over the range of 81.6 to 96.0 % with a relative standard deviation < 14.7 %. The detection and quantification limit ranged from 0.7 to 1.0 μg/kg and 1.0 to 5.0 μg/kg, respectively. The data showed that the first-order model was the best fit for the dissipation of five organophosphate pesticides with a regression coefficient of more than 0.99. The half-lives for all the studied pesticides were below 6.6 and 5.1 days for carrot and potato, respectively. The harvesting intervals for pesticides on the carrot and potato fields were within 28 and 21 days, respectively. The study results contribute to establishing the scientific basis of the dosage for organophosphate pesticide use in the vegetable field.