Department of Chemistry, The University of the West Indies, St. Augustine Campus, St. Augustine, Trinidad and Tobago.
Environ Monit Assess. 2020 Jan 21;192(2):128. doi: 10.1007/s10661-020-8072-1.
A newly modified QuEChERS method was developed, validated, and tested in-house for the multiclass, multiresidue determination of organophosphate (OPP) and organochlorine pesticide (OCP) residues in fruits and vegetables. The method incorporated a solvent extraction with acetonitrile followed by partitioning with magnesium sulphate (MgSO) and sodium chloride (NaCl). The final step involved a dispersive solid phase extraction (d-SPE) clean-up prior to gas chromatography with electron capture detection (GC-ECD) analysis. Apples and lettuce were the selected matrices for fruits and vegetables, respectively in the method development stages. Various combinations of sorbents were tested in the clean-up step. Florisil and MgSO (FM) d-SPE proved to be the best combination for the clean-up step for both OCPs and OPPs in both the fruit and vegetable matrices. Recovery values fell within the acceptable range of 70 to 120% (RSD ≤ 20%). The new method is unique as it employs the standard addition calibration technique for the quantification of OCP and OPP residues. Limit of detection, limit of quantification, linearity, recovery analysis, and repeatability were validation parameters used to evaluate the accuracy, precision, and ruggedness of the method. The newly modified QuEChERS method provides a cheaper alternative for the analysis of pesticide residues in fruits and vegetables as samples can be analysed at a fraction of the cost of the original QuEChERS method. The efficacy of the method was tested on several fruits and vegetables from the Central Division of Trinidad and Tobago. OCP and OPP residues were found in 61% of the samples, most of which were above the maximum residue limits.
一种新改良的 QuEChERS 方法已被开发、验证并在内部进行了多类、多残留的有机磷（OPP）和有机氯农药（OCP）在水果和蔬菜中的残留检测。该方法采用乙腈溶剂萃取，然后用硫酸镁（MgSO）和氯化钠（NaCl）进行分配。最后一步是在气相色谱电子捕获检测（GC-ECD）分析前进行分散固相萃取（d-SPE）净化。在方法开发阶段，苹果和生菜分别被选为水果和蔬菜的基质。在净化步骤中测试了各种吸附剂的组合。Florisil 和硫酸镁（FM）d-SPE 被证明是水果和蔬菜基质中 OCP 和 OPP 净化步骤的最佳组合。回收率在 70%至 120%（RSD≤20%）的可接受范围内。该新方法的独特之处在于它采用标准添加校准技术来定量 OCP 和 OPP 残留。检出限、定量限、线性、回收率分析和重复性是评估方法准确性、精密度和稳健性的验证参数。新改良的 QuEChERS 方法为水果和蔬菜中农药残留的分析提供了一种更经济的替代方法，因为与原始 QuEChERS 方法相比，样品的分析成本可以降低到一小部分。该方法已在特立尼达和多巴哥中部地区的几种水果和蔬菜上进行了测试。在 61%的样本中发现了 OCP 和 OPP 残留，其中大部分超过了最大残留限量。
