Pesticide Residue Research Group, EC Community Reference Laboratory for Pesicide Residues in Fruits and Vegetables Chemistry, University of Almeria, 04120, La Cañada de San Urbano, Almeria, Spain.
Talanta. 2011 Apr 15;84(2):262-73. doi: 10.1016/j.talanta.2010.12.006. Epub 2010 Dec 13.
In this paper, the influence of several operational parameters on a well established multiresidue LC-MS/MS method has been studied in relation to the analysis of 150 pesticides commonly present in vegetable samples. The operational parameters investigated are: (i) the influence of different modifiers (0.1% formic acid; 5mM ammonium formiate; 5mM ammonium acetate in aqueous phase) - both on the retention time and on the analytical response of the studied compounds; (ii) the effect of the analytical column's temperature on the retention time and on the analytical response of the pesticides investigated; (iii) the effects of co-elution in mixture containing 150 pesticides and, additionally, (iv) the carrying out of a study about the common transitions obtained by LC-MS/MS. Various common transitions were found among the 150 pesticides, but there were only two problematic cases, the pairs diuron-fluometuron and prometryn-terbutryn, which have common scanned transitions and have very close retention times. The use of ammonium salts as modifier instead of formic acid reports enhancement or suppression of the response depending on the pesticides. No great influence on the retention time or on the response of the pesticides and commodities studied was observed with relation to the column temperature. Two different columns: an HPLC (5 μm particle size) and an UHPLC analytical column (1.8 μm particle size) have been used. As was expected, shorter run times and lower peak width was achieved with the UHPLC column. In this paper, the effect of the compounds on each other in the MS analysis when the number of co-eluting compounds is quite high is also described. Mainly small suppression or enhancement co-elution effect was observed, but some particular pesticides presented high sensitivity (> ± 60% effect) when they elute together with others. This is an important factor and it has to be taken into account when performing multiresidue pesticide analysis.
本文研究了几种操作参数对一种成熟的多残留 LC-MS/MS 方法的影响，该方法与分析蔬菜样品中常见的 150 种农药有关。研究的操作参数包括：（i）不同修饰剂（0.1%甲酸；5mM 甲酸铵；水相中 5mM 乙酸铵）对研究化合物保留时间和分析响应的影响；（ii）分析柱温度对保留时间和研究农药分析响应的影响；（iii）在含有 150 种农药的混合物中出现的共洗脱的影响，以及（iv）进行关于 LC-MS/MS 获得的常见跃迁的研究。在 150 种农药中发现了各种常见的跃迁，但只有两种有问题的情况，即敌草隆-氟乐灵和普草隆-特丁津，它们具有共同的扫描跃迁且保留时间非常接近。与甲酸相比，使用铵盐作为修饰剂会根据农药的不同而增强或抑制响应。柱温对农药和研究商品的保留时间或响应几乎没有影响。使用了两种不同的柱子：一种是 HPLC（5μm 粒径），另一种是 UHPLC 分析柱（1.8μm 粒径）。正如预期的那样，UHPLC 柱的运行时间更短，峰宽更窄。本文还描述了当共洗脱化合物数量相当高时，化合物在 MS 分析中相互影响的情况。主要观察到小的抑制或增强共洗脱效应，但当某些特定农药与其他农药一起洗脱时，它们表现出高灵敏度（>±60%的效应）。这是一个重要因素，在进行多残留农药分析时必须考虑到这一点。
