Development and Validation of a Method for the Simultaneous Determination of 20 Organophosphorus Pesticide Residues in Corn by Accelerated Solvent Extraction and Gas Chromatography with Nitrogen Phosphorus Detection

Abstract

Abstract:The method for simultaneous determination of 20 organophosphorus pesticide residues in corn samples has been developed and validated. For the extraction of organophosporus pesticide residues from the samples, the accelerated solvent technique with the mixture of dichloromethane: acetone (1:1, V/V) was used. Clean up was done using liquid -liquid extraction with n -hexane, followed by solid phase extraction on primary secondary amine adsorbent, and elution with the mixture of acetone: toluene (65:35). The determination of the pesticides was carried out by gas chromatography with nitrogen phosphorus detection. Separation and quantitative determination of the analytes were performed on a fused silica capillary ZB-35 column (30 m x 0.25 mm i.d. x 0.25 µm, Phenomenex). The recovery was investigated in blank corn samples fortified with mevinphos, diazinon, dimethoate, bromofos-methyl, chlorfenvinphos, fenamiphos, ethion and phosalone at 5 ng/g, 10 ng/g, 15 ng/g , 20 ng/g and 25 ng/g, respectively and with methacrifos, phorate, etrimfos, parathion-methyl, pirimiphosmethyl, fenitrothion, chlorpyrifos, malathion, parathion, bromofos-ethyl, phosmet and azinphos-methyl at 10 ng/g, 20 ng/g, 30 ng/g, 40 ng/g and 50 ng/g, respectively. The recovery ranged from 76.0% to 112.0%. Repeatability expressed as relative standard deviation (RSD) was less than 8.2%. Linearity expressed as correlation coefficient (R 2 ) ranged from 0.9935 to 0.9996. Measurement uncertainty (U x ) was lower than 14.2% for all tested pesticides. The limits of quantification (LOQ) were bellow 5 ng/g for all tested pesticides. The satisfactory Z-score results of international proficiency tests confirm good analytical performances of the developed method.

Pressurized Liquid Extraction

“…A wide variety of pesticide residues were determined in different agricultural and food matrices by PLE, including honey [43], organophosphorus pesticide residues in corn [44], pyrethroid residues in complex feed samples [40], multiclass pesticides in Pressurized Liquid Extraction 383 food commodities and grain, or herbicides in soybeans [42]. Accurate determination of common organochlorine, organophosphorus, and pyrethroid pesticide residues in herbal samples like tea can be obtained by PLE coupled to gas chromatography/highresolution isotope dilution mass spectrometry [45].…”

Determination of fenthion in environmental water samples by dispersive liquid–liquid microextraction coupled with spectrofluorimetric and chemometrics methods

“…This method provides many advantages including rapidity, simplicity of operation, high recovery and enrichment factor. After sample preparation, the determination of OPPs in different sample matrices was carried out by using gas chromatography mass spectrometry (GC-MS) [9,22], gas chromatography (GC) [23][24][25] and high-performance liquid chromatography (HPLC) [26,27]. Fluorescence spectrometry is a sensitive, selective and relatively low cost method for the quantitative analysis of pesticides and other pollutants [28][29][30].…”