In this study, a modified Quick Polar Pesticides (QuPPe) method, optimized by a central composite design, was developed to determine quaternary ammonium pesticides (QUATs) residues in barley and wheat by ultra-high-performance liquid chromatographic tandem mass spectrometry (UHPLC-MS/MS) using a hydrophilic interaction chromatography (HILIC) column. Considering the high polarity of these compounds, special conditions of sample preparation and analysis are required. Different mobile phases, extraction procedure and clean-up were evaluated. An isocratic elution with aqueous solution of ammonium formate 60 mmol L⁻¹ (pH 3.7) and acetonitrile, 40:60 (v/v), was selected. Water and acidified methanol as extraction solvent, without heating, and a clean-up with dichloromethane, chitosan and acetonitrile presented good results. The validated method presented satisfactory selectivity, linearity, matrix effect, trueness and precision, providing recoveries from 93 to 110% with RSD < 13% for barley, and 70 to 115% with RSD < 18% for wheat. The complexity of these matrices requires the calibration in matrix and the diluted standard addition calibration (DSAC) procedure has been shown to be an excellent option to compensate for the matrix effect and the losses of the analytes in the extraction. Real samples of barley and wheat were analyzed and 60% presented concentrations of paraquat above the maximum limits allowed by the European Union. The modified QuPPe method combined with DSAC and HILIC-UHPLC-MS/MS demonstrated to be an effective approach to determine QUATs in barley and wheat, and is a good alternative for routine analysis. The use of the biosorbent chitosan is effective, low cost and more ecological when compared to others conventional sorbents.

在这项研究中，开发了一种改良的快速极性农药（QuPPe）方法，该方法通过中央复合设计进行了优化，可通过超高效液相色谱串联质谱（UHPLC-S）测定大麦和小麦中的季铵农药（QUATs）残留量。 MS / MS），使用亲水相互作用色谱（HILIC）柱。考虑到这些化合物的高极性，需要特殊的样品制备和分析条件。评估了不同的流动相，萃取程序和净化效果。甲酸铵水溶液60 mmol L ^-1的等度洗脱（pH 3.7）和乙腈选择为40:60（v / v）。将水和酸化的甲醇用作萃取溶剂，无需加热，用二氯甲烷，脱乙酰壳多糖和乙腈进行净化的效果很好。经过验证的方法具有令人满意的选择性，线性，基质效应，真实性和精密度，大麦的RSD <13％时回收率从93％到110％，小麦的RSD <18％时回收率从70％到115％。这些基质的复杂性要求在基质中进行校准，并且稀释的标准添加校准（DSAC）程序已被证明是补偿基质效应和萃取物中分析物损失的极佳选择。分析了大麦和小麦的真实样品，其中60％的百草枯浓度超过了欧盟允许的最大限量。改进的QuPPe方法与DSAC和HILIC-UHPLC-MS / MS结合使用，是确定大麦和小麦QUAT的有效方法，是常规分析的良好替代方法。与其他常规吸附剂相比，壳聚糖生物吸附剂的使用有效，成本低廉且更加生态。