Evaluation and statistical analysis of the modified QuEChERS method for the extraction of pinoxaden from environmental and agricultural samples

Background: Green chemistry focuses on an efficient extraction strategy for pesticides from agricultural and environmental samples. QuEChERS (quick, easy, cheap, effective, rugged, and safe) method is used primarily, in the extraction of pesticides from food matrices. Certain modifications in the approach lead to better sensitivity and efficient extraction. This paper describes an analytical approach for spectrophotometric determination of pinoxaden herbicide in different matrices based on a modified QuEChERS method. Methods: The original QuEChERS method was modified using different buffering media and different cleanup sorbents. Efficacy of different dispersive SPE sorbents for the cleanup was compared. The optimized conditions were applied for investigation of percent recovery and residue analysis. The presence of the residue was confirmed by employing two reported HPLC methods under optimized conditions. Statistical analysis of the data was accomplished to investigate the distribution of the subject analyte in soil. Results: The average percent recovery of pinoxaden was found to be in the range of 77 ± 5% to 100 ± 2% for soil, 84 ± 2% to 98 ± 2% for water samples, and 79 ± 1% to 88 ± 1% for wheat grains. Good linearity with R = 0.997 was achieved in acetate buffer system. Limits of detection of pinoxaden in soil, water, and wheat grain samples were found to be 0.6 μg/g, 0.48 μg/mL, and 0.31 μg/g, respectively, while limits of quantification in the above matrices were found to be 1.83 μg/g, 1.46 μg/mL, and 0.94 μg/g respectively. Statistical analysis of the data using a three-way ANOVA shows that the individual impacts of cardinal axis and time on distribution of pinoxaden (PXD) residue is statistically insignificant. However, the impact of depth on PXD residue was found to be highly significant as the p value <0.01. The interaction of the sampling time and depth of soil was found to have highly significant effect on the PXD residue in soil sample. Conclusions: The proposed method is a milestone in the extraction of pinoxaden, a relatively new pesticide, from agricultural and environmental samples in terms of simplicity, sensitivity, and reproducibility.