Ferrer Imma, Fernandez-Alba Amadeo, Zweigenbaum Jerry A, Thurman E Michael
Pesticide Residue Research Group, Department of Analytical Chemistry, University of Almería, 04120 Almería, Spain.
Rapid Commun Mass Spectrom. 2006;20(24):3659-68. doi: 10.1002/rcm.2781.
An automated molecular-feature database (MFD) consisting of the exact monoisotopic mass of 100 compounds, at least one exact mass product ion for each compound, and chromatographic retention time were used to identify pesticides in food and water samples. The MFD software compiles a list of accurate mass ions, excludes noise, and compares them with the monoisotopic exact masses in the database. The screening criteria consisted of +/-5 ppm accurate mass window, +/-0.2 min retention time window, and a minimum 1000 counts (signal-to-noise (S/N) ratio of approximately 10:1). The limit of detection for 100 tested compounds varied from <0.01 mg/kg for 72% of the compounds to <0.1 mg/kg for 95% of the compounds. The MFD search was useful for rapid screening and identification of pesticides in food and water, as shown in actual samples. The combined use of accurate mass and chromatographic retention time eliminated false positives in the automated analysis. The major weakness of the MFD is matrix interferences and loss of mass accuracy. Strengths of the MFD include rapid screening of 100 compounds at sensitive levels compared with a manual approach and the ease of use of the library for any accurate mass spectrometer instrumentation capable of routine sub-5-ppm mass accuracy.
一个自动化分子特征数据库（MFD），它包含100种化合物的精确单同位素质量、每种化合物至少一个精确质量的产物离子以及色谱保留时间，用于识别食品和水样中的农药。MFD软件会编制一份精确质量离子列表，排除噪声，并将其与数据库中的单同位素精确质量进行比较。筛选标准包括±5 ppm的精确质量窗口、±0.2分钟的保留时间窗口以及至少1000计数（信噪比约为10:1）。100种测试化合物的检测限从72%的化合物低于0.01 mg/kg到95%的化合物低于0.1 mg/kg不等。如实际样品所示，MFD搜索对于食品和水中农药的快速筛选和识别很有用。精确质量和色谱保留时间的联合使用消除了自动分析中的假阳性。MFD的主要缺点是基质干扰和质量准确性的损失。MFD的优点包括与手动方法相比能够在灵敏水平上快速筛选100种化合物，并且该库易于用于任何能够实现常规低于5 ppm质量准确性的精确质量光谱仪仪器。
