Multiresidue determination of pyrethroid pesticide residues in pepper through a modified QuEChERS method and gas chromatography with electron capture detection

Abstract

This study developed and used a modified quick, easy, cheap, efficient, rugged and safe (QuEChERS) method coupled with gas chromatography with electron capture detection to determine eight pyrethroid pesticide residues in green, red and dehydrated red peppers. Pyrethroids were extracted with acetonitrile, partitioned with sodium chloride and purified with primary secondary amino and graphitized carbon black in hexane. The QuEChERS extraction conditions were optimized, and the matrix effects that might influence recoveries were evaluated and minimized using matrix-matched calibration curves. Under the optimized conditions, the calibration curves for pyrethroid pesticides showed good linearities in the concentration range of 0.05-20 µg/mL with determination coefficients (R(2) ) >0.997. The limits of quantification of eight pyrethroids were 0.004-0.04 mg/kg for green and red pepper and 0.04-0.5 mg/kg for dehydrated red pepper. These values are below the suggested regulatory maximum residue limits. The mean recoveries ranged between 79.0 and 104%, and the relative standard deviations were <11%. The developed method was successfully applied to commercial samples. Some samples were found to contain pyrethroid pesticides with levels below the legal limits.

Co-Metabolic Degradation of β-Cypermethrin and 3-Phenoxybenzoic Acid by Co-Culture of Bacillus licheniformis B-1 and Aspergillus oryzae M-4

“…Pyrethroid pesticides are the most widely used insecticides, and their residues are consistently detected in fruits and vegetables, rivers, and soil as a result of excessive spraying [1, 2]. Hladik et al [3] reported that the concentrations of pyrethroids in bed sediments from urban and agricultural streams across the United States ranged from 0.3 to 180 ng/g dry weight.…”

Dissipation and residue determination of penicillin G and its two metabolites in citrus under field conditions by DSPE/UPLC–MS/MS

“…The matrix effects (ME) were calculated by comparing the slopes of the calibration curves in the solvent and in the matrix. Values for ME of <1, 1.0 and >1 indicated signal suppression, no matrix effect and signal enhancement, respectively (Zhang et al, 2016). Penillic acid showed a slight signal enhancement (1.07, 1.08 and 1.02 of ME in peel, pulp and whole fruit, respectively) in citrus, whereas penicillin G (0.58, 0.85 and 0.66 of ME in peel, pulp and whole fruit, respectively) and penilloic acid (0.85, 0.81 and 0.71 of ME in peel, pulp and whole fruit, respectively) both showed obvious matrix suppression (Table 2).…”

Residual level of dimethachlon in rice‐paddy field system and cooked rice determined by gas chromatography with electron capture detector

“…Matrix effects (MEs) including matrix enhancement or matrix suppression are common problems in GC and thus influence the reproducibility and accuracy of the method. The ME was calculated by comparing the slope of the matrix–matched standard curve with the slope of the solvent standard curve (Zhang et al, ). Satisfactory linear relationships and coefficients of determination ( R 2 > 0.996) were achieved (Table ).…”