Analytical Chemistry Research Group, Department of Physical and Analytical Chemistry, University of Jaén, Campus Las Lagunillas, Edificio B-3, 23071 Jaén, Spain.
J Chromatogr A. 2010 Sep 24;1217(39):6022-35. doi: 10.1016/j.chroma.2010.07.062. Epub 2010 Aug 1.
In this work we have evaluated the performance of two sample preparation methodologies for the large-scale multiresidue analysis of pesticides in olives using liquid chromatography-electrospray tandem mass spectrometry (LC-MS/MS). The tested sample treatment methodologies were: (1) liquid-liquid partitioning with acetonitrile followed by dispersive solid-phase extraction clean-up using GCB, PSA and C18 sorbents (QuEChERS method - modified for fatty vegetables) and (2) matrix solid-phase dispersion (MSPD) using aminopropyl as sorbent material and a final clean-up performed in the elution step using Florisil. An LC-MS/MS method covering 104 multiclass pesticides was developed to examine the performance of these two protocols. The separation of the compounds from the olive extracts was achieved using a short C18 column (50 mm x 4.6 mm i.d.) with 1.8 microm particle size. The identification and confirmation of the compounds was based on retention time matching along with the presence (and ratio) of two typical MRM transitions. Limits of detection obtained were lower than 10 microgkg(-1) for 89% analytes using both sample treatment protocols. Recoveries studies performed on olives samples spiked at two concentration levels (10 and 100 microgkg(-1)) yielded average recoveries in the range 70-120% for most analytes when QuEChERS procedure is employed. When MSPD was the choice for sample extraction, recoveries obtained were in the range 50-70% for most of target compounds. The proposed methods were successfully applied to the analysis of real olives samples, revealing the presence of some of the target species in the microgkg(-1) range. Besides the evaluation of the sample preparation approaches, we also discuss the use of advanced software features associated to MRM method development that overcome several limitations and drawbacks associated to MS/MS methods (time segments boundaries, tedious method development/manual scheduling and acquisition limitations). This software feature recently offered by different vendors is based on an algorithm that associates retention time data for each individual MS/MS transition, so that the number of simultaneously traced transitions throughout the entire chromatographic run (dwell times and sensitivity) is maximized.
在这项工作中，我们评估了两种样品前处理方法在使用液相色谱-电喷雾串联质谱（LC-MS/MS）对橄榄中多种农药残留进行大规模多残留分析中的性能。所测试的样品处理方法如下：（1）用乙腈进行液-液萃取，然后用 GCB、PSA 和 C18 吸附剂进行分散固相萃取净化（适用于高脂肪蔬菜的 QuEChERS 方法改良版）；（2）基质固相分散（MSPD），使用氨基丙基作为吸附材料，最后在洗脱步骤中用 Florisil 进行净化。开发了一种 LC-MS/MS 方法，可检测这两种方案的性能，该方法涵盖了 104 种多类农药。使用短 C18 柱（50mmx4.6mmid.，1.8μm 粒径）实现化合物与橄榄提取物的分离。化合物的鉴定和确证基于保留时间匹配以及两个典型的 MRM 转换的存在（和比例）。使用这两种样品处理方案，在 10 和 100μgkg(-1)两个浓度水平下对橄榄样品进行加标回收率研究，得到的检测限均低于 10μgkg(-1)。对于大多数分析物，当使用 QuEChERS 方法时，回收率在 70-120%的范围内；而当选择 MSPD 进行样品提取时，大多数目标化合物的回收率在 50-70%的范围内。所提出的方法成功应用于实际橄榄样品的分析，揭示了一些目标化合物在μgkg(-1)范围内的存在。除了对样品制备方法进行评估外，我们还讨论了与 MRM 方法开发相关的先进软件功能的使用，这些功能克服了与 MS/MS 方法相关的几个限制和缺点（时间片段边界、繁琐的方法开发/手动调度和采集限制）。这种由不同供应商最近提供的软件功能基于一种算法，该算法将每个单个 MS/MS 转换的保留时间数据相关联，从而最大限度地提高整个色谱运行过程中同时追踪的转换数量（驻留时间和灵敏度）。
