Chawla Suchi, Patel Hemlatta K, Gor Hetal N, Vaghela Kiran M, Solanki Priti P, Shah Paresh G
Anand Agricultural University, All India Network Project on Pesticide Residues, Pesticide Residue Laboratory, Anand, Gujarat, India 388 110.
J AOAC Int. 2017 May 1;100(3):616-623. doi: 10.5740/jaoacint.17-0048. Epub 2017 Mar 16.
The study was conducted to investigate matrix interferences using QuEChERS sample preparation to understand whether the dilution of matrix and/or the grouping of commodities can eliminate the need for selective individual matrix-matched standards in LC with tandem MS (MS/MS) analysis, and whether the calibration graph based on only one matrix can be used for quantification in the other matrixes. Matrix effects (MEs) were studied by comparing the slopes of calibration curves of the matrix-matched standards (diluted with mobile phase) vis-à-vis the solvent-based standards. The present study showed that MEs were dependent on the nature of both the commodity and the analyte. Among the test matrixes, the highest variability in ME was recorded in capsicum. Most of the pesticides showed signal suppression in tomato, capsicum, and cumin matrixes. In brinjal matrix, the signal of most of the pesticides showed slight enhancement. Due to the similar nature of the MEs in tomato and capsicum, these two commodities can be grouped together. Considering analyte variability, acetamiprid, 3-hydroxy carbofuran, dichlorvos, dimethoate, and spinosyn A and D showed no significant ME (≤20%) in tomato. Very high MEs (2360.9 and 1250.8%) were observed for quizalofop-p-tefuryl and tebuconazole, respectively. To check the effect of dilution in minimizing the ME, cucumber and brinjal matrixes were diluted 10×, and calibration curves were drawn with five concentration levels. It was found that about 60% of the total analyzed pesticides showed MEs ≤20%. In cumin, MEs ranged from -5.3% for triazophos to 661% for thiacloprid. Most of the pesticides showed recoveries in the acceptable range of 70-130% with calibration curves from both matrixes. To compensate for MEs, it is suggested that (1) tomato and capsicum matrixes, which show similar trends, can be grouped together; and (2) cucumber matrix, when diluted 10×, can be used to prepare calibration curves for the quantification of pesticides in various fruiting and cucurbit vegetable matrixes by LC-MS/MS.
开展该研究是为了使用QuEChERS样品制备方法来调查基质干扰，以了解基质稀释和/或商品分组是否能够消除液相色谱串联质谱（MS/MS）分析中对选择性个体基质匹配标准品的需求，以及基于单一基质的校准曲线是否可用于其他基质的定量分析。通过比较基质匹配标准品（用流动相稀释）与溶剂标准品的校准曲线斜率来研究基质效应（MEs）。本研究表明，基质效应取决于商品和分析物的性质。在测试基质中，辣椒的基质效应变化最大。大多数农药在番茄、辣椒和孜然基质中表现出信号抑制。在茄子基质中，大多数农药的信号略有增强。由于番茄和辣椒中的基质效应性质相似，这两种商品可以归为一组。考虑到分析物的变异性，啶虫脒、3-羟基克百威、敌敌畏、乐果以及多杀菌素A和D在番茄中未表现出显著的基质效应（≤20%）。喹禾糠酯和戊唑醇分别观察到非常高的基质效应（2360.9%和1250.8%）。为了检查稀释对最小化基质效应的影响，将黄瓜和茄子基质稀释10倍，并绘制了五个浓度水平的校准曲线。结果发现，约60%的分析农药的基质效应≤20%。在孜然中，基质效应范围从三唑磷的-5.3%到噻虫啉的661%。大多数农药在两种基质的校准曲线下回收率在70 - 130%的可接受范围内。为了补偿基质效应，建议：（1）表现出相似趋势的番茄和辣椒基质可以归为一组；（2）黄瓜基质在稀释10倍后可用于通过液相色谱-质谱/质谱法为各种结果实的蔬菜和葫芦科蔬菜基质中的农药定量制备校准曲线。
