Sin-QuEChERS结合UPLC-MS/MS同时检测茶叶中10种有机磷农药残留

Simultaneously Detection of 10 Organophosphorus Pesticides Residues in Tea by Sin-QuEChERS with UPLC-MS/MS

基于茶叶样品基质复杂的特点,采用简易的基质分散净化(Sin-QuEChERS)法对样品前处理技术加以改进,并结合超高效液相色谱-串联质谱(UPLC-MS/MS)技术,建立了同时检测茶叶中10种有机磷农药残留的分析方法。与传统的样品预处理方法相比,该方法在保证重复性和稳定性的前提下,具有操作简单、省时省力、普适性好、灵敏度高等优点。在优化的Sin-QuEChERS方法提取净化条件和UPLC-MS/MS检测条件下,可将样品前处理时间控制在10min以内,使每个样品的分析在0.5h内完成。结果表明:10种有机磷农药的线性范围为1~500μg/L,检出限为0.08~1.38μg/kg,定量限为0.27~4.60μg/kg;在不同的加标水平下,平均回收率在71.6%~115.0%之间,RSD小于14.5%,与国家标准方法的检测结果接近。将该方法应用于检测空白茶叶加标样品和20种市售茶叶中有机磷农药,验证了方法的可行性。该研究可为快速、简易、准确地评价茶叶中多种有机磷类农药的质量安全提供方法参考。

Based on the characteristics of tea samples, a method was established for simultaneously detection of 10 organophosphorus pesticides residues (dimethoate, omethoate, phosemet, malathion, dipterex, dichlorovos, quinalphos, demeton, methamidophos, monocrotophos). In this method, a novel pretreatment method of Sin-QuEChERS was used for extraction and purification, and ultra-high performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) technology was used for detection. In view of the strong matrix effect of tea samples and the characteristics of organophosphorus pesticide decomposition with heat, a packing column filled with PSA, C18, carbon multiwalled nanotubes (CMWNTs) was applied in the Sin-QuEChERS methods. After an ordinary extraction by acetonitrile, vortex oscillation and centrifugation, the purification of chlorophyll, lutein and tea polyphenols in tea leaves was processed with a simple pressing of the Sin-QuEChERS packing column. The purified solution can be directly injected into the detector. This Sin-QuEChERS method can improve the removal effect of matrix interference by SPE, improve the purification effect of pigments, lipids and some sugar sterols, and reduce the interference of chromatogram. Compared with other extraction and purification methods, it has the advantages of simple operation, obvious purification effect on impurities, less adsorption on pesticides and accurate results, and can greatly shorten the analysis time. At the same time, because this method does not involve heating and other links, it is suitable for temperature decomposition of organophosphorus pesticides extraction and purification operation, and is able to improve the accuracy of organophosphorus pesticides detection results. In the optimized Sin-QuEChERS methods and UPLC-MS/MS detection conditions, the preprocessing time can be controlled within 10 min, so that the analysis time of a sample can be completed within the 0.5 h. The linear range of 10 organophosphorus pesticides is 1-500 μg/L. The limit of detection (LOD) is 0.08-1.38 μg/kg, and the limit of quantity (LOQ) is 0.27-4.60 μg/kg. The recoveries are 71.6%-115.0% and RSDs of different spiking levels are less than 14.5%. Compared with the traditional sample pretreatment method, the new developed method has the advantages of simple operation, time- saving, good universality and high sensitivity with the premise of ensuring repeatability. The method was applied for the detection of organophosphorus pesticides in standard addition of blank tea samples and 20 kinds of tea, which proved the feasibility and importance of the method. This method provides a new way to evaluate the quality and safety of tea more quickly, simply, cheaply and accurately.