Dispersive micro Solid-Phase extraction with Bimetallic Ni, Zn-MOF sorbent and gas chromatography method for Organophosphorus pesticide determination in environmental water samples

Abstract

Listen

Translate article

A dispersive micro solid-phase extraction coupled with the GC-FID method was developed to determine three Organophosphorus pesticides: Fenitrothion, Chlorpyrifos, and Diazinon. Various sorbents, including Fe3O4 NPs, Zn-MOF, Ni-MOF, Bimetallic Ni, Zn-MOF, and Fe3O4 NPs@SiO2@ Bimetallic Ni, Zn-MOF, were synthesized and evaluated for their extraction efficiency of OPPs. Fe3O4 NPs@SiO2@ Bimetallic Ni, Zn-MOF was identified as the optimal sorbent based on its performance. The affective factors in the procedure were optimized using one factor of the time and experimental design methods. The significant factors in this method included sorbent amount, extraction time, and desorption solvent volume with an optimum value of 37 mg, 8.3 min, and 231 µL, respectively. Under optimized conditions, the method exhibited distinct linear ranges for Fenitrothion, Chlorpyrifos, and Diazinon, ranging from 0.24 to 259, 0.17–234, and 0.25–247 ng mL−1, respectively, with high corresponding R2 values (0.9947, 0.9929, and 0.9943). The limits of detection (LOD) were determined based on three times the standard deviation of the blank sample divided by the slope of the calibration curve for each OPP to be 0.07, 0.05, and 0.07 ng mL−1 for Fenitrothion, Chlorpyrifos, and Diazinon, respectively, while the limits of quantification (LOQ) were 0.24, 0.17, and 0.25 ng mL−1. Precision was assessed by calculating intra-day and inter-day relative standard deviation (RSD%) values in one day and three consecutive days with three replicates of each analysis for three concentrations of 10, 25, and 50 ng mL−1, which were found to be below 4.27 %, 4.35 %, and 4.32 % for Fenitrothion, Chlorpyrifos, and Diazinon, respectively, for intra-day analysis, and below 5.43 %, 5.11 %, and 5.29 % for inter-day analysis, respectively. Additionally, the enrichment factor (EF) values for Fenitrothion, Chlorpyrifos, and Diazinon with a concentration of 20 ng mL−1 were determined to be 78.6, 82.4, and 75.7, respectively. Analysis of spiked real samples in two concentrations of 5.0 or 25.0 ng mL−1, such as tap water, river water, dam water, and well water, revealed recovery percentages in the range of 91.2 % to 97.7 %, with relative standard deviations ranging from 3.79 % to 4.98 %, further validating the method’s reliability for practical applications. Overall, the method provides wide linearity, low LODs and LOQs, responsible RSDs, high EFs, and proper recovery percentages for determining OPPs.