Here we describe the improvement of pesticide residue extraction from tomatoes by an improved QuEChERS method. Through Plackett–Burman design, 4 significant variables out of 11 potential variables were identified that could influence the relative deviation of measurements. The 11 variables were: amount of sample, C₁₈, Na₂SO₄, NaCl, MgSO₄, NaAc, GCB (graphitized carbon black), and PSA (primary–secondary amine); ACN volume; percentage of FA (formic acid); and centrifugation time. The amounts of GCB, Na₂SO₄, PSA and sample were significant variables, which were further optimized using a Box–Behnken design to predict the optimum extraction conditions. The method presented recoveries between 72.5 and 119.7%, with relative standard deviations ranging from 1.17 to 14.62% for all real samples spiked with pesticides at three different fortification levels. Overall, methods met the requirements of national standard for pesticide residue analysis. The results indicate that the improved QuEChERS method is suitable for the routine monitoring of 20 pesticides which often are detected in tomato samples.

中文翻译：

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开发使用QuEChERS和GC-MS / MS测定番茄中农药多残留的快速方法

在这里，我们描述了通过改进的QuEChERS方法从西红柿中提取农药残留的方法。通过Plackett-Burman设计，从11个潜在变量中识别出4个重要变量，这些变量可能影响测量的相对偏差。11个变量是：样品量，C ₁₈，Na ₂ SO ₄，NaCl，MgSO ₄，NaAc，GCB（石墨化炭黑）和PSA（伯-仲胺）；乙腈体积; FA（甲酸）的百分比；和离心时间。GCB，Na ₂ SO ₄的含量，PSA和样品是重要的变量，使用Box–Behnken设计对其进行了进一步优化以预测最佳提取条件。该方法的回收率在72.5％至119.7％之间，对于在三个不同的设防水平下加有农药的所有真实样品，其相对标准偏差为1.17％至14.62％。总体而言，方法符合农药残留分析国家标准的要求。结果表明，改进的QuEChERS方法适用于常规监测番茄样品中经常检测到的20种农药。