Schurek Jakub, Vaclavik Lukas, Hooijerink H Dick, Lacina Ondrej, Poustka Jan, Sharman Matthew, Caldow Marianne, Nielen Michel W F, Hajslova Jana
Department of Food Chemistry and Analysis, Institute of Chemical Technology Prague, 6 Prague 16628, Czech Republic.
Anal Chem. 2008 Dec 15;80(24):9567-75. doi: 10.1021/ac8018137.
Ambient mass spectrometry has been used for the analysis of strobilurin residues in wheat. The use of this novel, challenging technique, employing a direct analysis in a real time (DART) ion-source coupled with a time-of-flight mass spectrometer (TOF MS) and a desorption electrospray ionization (DESI) source coupled with a linear ion trap tandem MS (LIT MS(n)), permitted a direct screen of the occurrence of target fungicides in treated grains in less than 1 min. For quantification purpose by DART-TOF MS, an ethyl acetate extract had to be prepared. With the use of a prochloraz as an internal standard, the performance characteristics obtained by repeated analyses of extract, spiked at 50 microg kg(-1) with six strobilurins (azoxystrobin, picoxystrobin, dimoxystrobin, kresoxim-methyl, pyraclostrobin, and trifloxystrobin), were in the following range: recoveries 78-92%, repeatability (RSD) 8-15%, linearity (R(2)) 0.9900-0.9978. The analysis of wheat with incurred strobilurin residues demonstrated good trueness of data generated by the DART-TOF MS method; the results were in a good agreement with those obtained by the conventional approach, i.e., by the QuEChERS sample handling procedure followed by identification/quantification employing high-performance liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). Tandem mass spectrometry using DESI-LIT MS(n) provided a sufficient number of product ions for confirmation of the identity of azoxystrobin and pyraclostrobin in incurred wheat samples.
环境质谱法已用于分析小麦中的甲氧基丙烯酸酯类残留。使用这种新颖且具有挑战性的技术，即采用实时直接分析（DART）离子源与飞行时间质谱仪（TOF MS）联用，以及解吸电喷雾电离（DESI）源与线性离子阱串联质谱（LIT MS(n)）联用，能够在不到1分钟的时间内直接筛查处理过的谷物中目标杀菌剂的存在情况。为了通过DART-TOF MS进行定量分析，必须制备乙酸乙酯提取物。以咪鲜胺作为内标，对添加了六种甲氧基丙烯酸酯类（嘧菌酯、啶氧菌酯、醚菌酯、醚菌酯、吡唑醚菌酯和肟菌酯）且浓度为50 μg kg⁻¹的提取物进行重复分析，得到的性能特征如下：回收率78 - 92%，重复性（相对标准偏差，RSD）8 - 15%，线性（R²）0.9900 - 0.9978。对含有甲氧基丙烯酸酯类残留的小麦进行分析表明，DART-TOF MS方法生成的数据具有良好的准确性；结果与通过传统方法获得的结果高度一致，即通过QuEChERS样品处理程序，随后采用高效液相色谱-串联质谱（LC-MS/MS）进行鉴定/定量。使用DESI-LIT MS(n)的串联质谱法提供了足够数量的产物离子，用于确认受污染小麦样品中嘧菌酯和吡唑醚菌酯的身份。
