Pecan nut is a crop of growing economic importance with a worldwide production around 124,000 tons during the 2017/2018 harvest. Thus, a simple and fast method for the determination of pesticide residues in this crop based on a QuEChERS sample preparation procedure and liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis was developed and validated. Despite the complexity of this matrix, with high fat content, the method was suitable to analyze 47 compounds in pecan nuts employing original QuEChERS salts and clean-up with the sorbents PSA and C18. This combination showed best results for lipid removal and compound recoveries when compared with the sorbents Z-Sep+, EMR-Lipid®, chitosan, diatomaceous earth, silica, and Florisil®. Validation was performed according to SANTE guideline using blank samples spiked at 5, 10, 20, 50, and 100 μg kg⁻¹, and the proposed method presented satisfactory results with recoveries for most of the pesticides in the range of 70–120% with RSD < 20% and practical limits of quantification from 5 to 10 μg kg⁻¹ for all compounds. The method was successfully applied in real samples and demonstrated to be simple, robust, and effective to be applied in routine analysis.

中文翻译：

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改进的QuEChERS方法用于液相色谱串联质谱法测定山核桃果仁中的农药

山核桃是一种日益重要的经济作物，2017/2018年度收成的全球产量约为124,000吨。因此，开发并验证了一种基于QuEChERS样品制备程序和液相色谱串联质谱（LC-MS / MS）分析的测定农作物中农药残留的简单快速的方法。尽管该基质复杂且脂肪含量高，但该方法仍适用于使用原始QuEChERS盐分析山核桃坚果中的47种化合物，并用PSA和C18吸附剂进行净化。与吸附剂Z-Sep +，EMR-Lipid®，脱乙酰壳多糖，硅藻土，二氧化硅和Florisil®相比，此组合显示出最佳的脂质去除和化合物回收率结果。根据SANTE指南，使用加标成5、10、20、50，^-1，并且所提出的方法显示了令人满意的结果，大多数农药的回收率在70–120％范围内，RSD <20％，并且所有化合物的实际定量限为5至10μgkg ^-1。该方法已成功应用于实际样品中，并被证明简单，稳健并且有效地应用于常规分析。