Combating matrix effects in LC/ESI/MS: The extrapolative dilution approach
Combating matrix effects in LC/ESI/MS: The extrapolative dilution approach
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DOI：
10.1016/j.aca.2009.07.060
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发表时间：
2009-09-28
影响因子：
6.2
通讯作者：
Herodes, Koit
中科院分区：
文献类型：
--
作者：
Kruve, Anneli;Leito, Ivo;Herodes, Koit
液相色谱电喷雾质谱- LC/ESI/MS-分析困难基质中低挥发性化合物的主要工具-在ESI电离中遭受基质效应。众所周知，基质效应可以通过样品稀释来降低。然而，简单的样品稀释的效率往往是有限的，特别是由该方法的检测限，并可以强烈地从样品到sample.In本研究中的基质效应作为稀释度的函数进行了研究。结果表明，在某些情况下，稀释可以消除基体效应，但往往只是降低基体效应。在此基础上，我们提出了一种基于连续稀释样品并将待测物含量外推至无限稀释即无基质溶液的新定量方法，并将该方法用于5种农药的LC/ESI/MS分析（灭多威、噻菌灵、涕灭威、抑霉唑、甲硫威）（番茄、黄瓜、苹果、黑麦和大蒜）。发现所有样品的分析浓度和加标浓度之间一致。结果表明，外推稀释法在测定结果的准确性方面明显优于简单的样品稀释法，该方法主要用于（a）方法开发/验证，以确定基质效应的程度和克服基质效应的方法;（B）在分析物含量接近最大残留限量（MRL）的情况下，作为分析的第二步. (C)2009 Elsevier B. V.保留所有权利。
Liquid chromatography electrospray mass spectrometry - LC/ESI/MS-a primary tool for analysis of low volatility compounds in difficult matrices - suffers from the matrix effects in the ESI ionization. It is well known that matrix effects can be reduced by sample dilution. However, the efficiency of simple sample dilution is often limited, in particular by the limit of detection of the method, and can strongly vary from sample to sample.In this study matrix effect is investigated as the function of dilution. It is demonstrated that in some cases dilution can eliminate matrix effect, but often it is just reduced. Based on these findings we propose a new quantitation method based on consecutive dilutions of the sample and extrapolation of the analyte content to the infinite dilution, i.e. to matrix-free solution.The method was validated for LC/ESI/MS analysis of five pesticides (methomyl, thiabendazole, aldicarb, imazalil, methiocarb) in five matrices (tomato, cucumber, apple, rye and garlic) at two concentration levels (0.5 and 5.0 mg kg(-1)). Agreement between the analyzed and spiked concentrations was found for all samples. It was demonstrated that in terms of accuracy of the obtained results the proposed extrapolative dilution approach works distinctly better than simple sample dilution.The main use of this approach is envisaged for (a) method development/validation to determine the extent of matrix effects and the ways of overcoming them and (b) as a second step of analysis in the case of samples having analyte contents near the maximum residue limits (MRL). (C) 2009 Elsevier B.V. All rights reserved.