Organophosphorus Pesticide Multiresidues in Commercialized Asian Rice

Abstract

The organophosphorus pesticides (OPPs) commonly used in agricultural practices can pose a risk of potential exposure to humans via food consumption. We describe an analytical method for solid-phase extraction coupled with highperformance liquid chromatography-diode array detector (SPE-HPLC-DAD) for the detection of OPPs (quinalphos, diazinon, and chlorpyrifos) in rice grains. The isolation of targeted residues was initiated with double extraction before SPE-HPLC-DAD, crucially reducing matrix interferences and detecting a wide range of multiple residues in rice grains. Coefficients of 0.9968 to 0.9991 showed a strong linearity, with limits of detection and quantification ranging from 0.36 to 0.68 µg/kg and from 1.20 to 2.28 µg/kg, respectively. High recoveries (80.4-110.3%) were observed at 3 spiking levels (50, 100, and 200 µg/kg), indicating good accuracy. The relative standard deviations of all residues (0.19-8.66%) validated the method precision. Sample analysis of 10 rice grain types (n = 30) available in the Asian market revealed that quinalphos, diazinon, and chlorpyrifos at concentrations of 1.08, 1.11, and 1.79 µg/kg, respectively, remained far below the maximum residue limits (0.01-0.5 mg/kg). However, regular monitoring is necessary to confirm that multiresidue occurrence remains below permissible limits while controlling pests.

Development of a single‐run liquid chromatography‐mass spectrometry analysis for the detection of 11 multiclass contaminants of emerging concern using a direct filtration method

“…The filtration can be combined with other sample preparation techniques to increase recovery and determine the CECs at ng/L levels. For example, several sample preparation techniques, such as SPE, SPME, and the QUECHERS method, also involve the filtration of samples using a syringe filter before LC-MS/GC-MS/HPLC analysis [6,9,[33][34][35][36]. Moreover, pre-treatment of the filters to pre-saturate or inhibit the available binding sites for CECs on the membrane is one strategy to reduce CEC sorption.…”