Office of Regulatory Science, Center for Food Safety and Applied Nutrition, US Food and Drug Administration, College Park, Maryland 20740, United States.
Anal Chem. 2012 Jul 3;84(13):5677-84. doi: 10.1021/ac300844d. Epub 2012 Jun 21.
Modern determination techniques for pesticides must yield identification quickly with high confidence for timely enforcement of tolerances. A protocol for the collection of liquid chromatography (LC) electrospray ionization (ESI)-quadruple linear ion trap (Q-LIT) mass spectrometry (MS) library spectra was developed. Following the protocol, an enhanced product ion (EPI) library of 240 pesticides was developed by use of spectra collected from two laboratories. A LC-Q-LIT-MS workflow using scheduled multiple reaction monitoring (sMRM) survey scan, information-dependent acquisition (IDA) triggered collection of EPI spectra, and library search was developed and tested to identify the 240 target pesticides in one single LC-Q-LIT MS analysis. By use of LC retention time, one sMRM survey scan transition, and a library search, 75-87% of the 240 pesticides were identified in a single LC/MS analysis at fortified concentrations of 10 ng/g in 18 different foods. A conventional approach with LC-MS/MS using two MRM transitions produced the same identifications and comparable quantitative results with the same incurred foods as the LC-Q-LIT using EPI library search, finding 1.2-49 ng/g of either carbaryl, carbendazim, fenbuconazole, propiconazole, or pyridaben in peaches; carbendazim, imazalil, terbutryn, and thiabendazole in oranges; terbutryn in salmon; and azoxystrobin in ginseng. Incurred broccoli, cabbage, and kale were screened with the same EPI library using three LC-Q-LIT and a LC-quadruple time-of-flight (Q-TOF) instruments. The library search identified azoxystrobin, cyprodinil, fludioxinil, imidacloprid, metalaxyl, spinosyn A, D, and J, amd spirotetramat with each instrument. The approach has a broad application in LC-MS/MS type targeted screening in food analysis.
现代农药检测技术必须快速、高置信度地进行鉴定，以便及时执行残留限量。本文开发了一种用于收集液相色谱（LC）电喷雾电离（ESI）-四重线性离子阱（Q-LIT）质谱（MS）谱库谱的方案。按照该方案，使用两个实验室收集的谱图，开发了 240 种农药的增强型产物离子（EPI）谱库。建立了一种 LC-Q-LIT-MS 工作流程，采用预定多重反应监测（sMRM）全扫描、信息依赖采集（IDA）触发 EPI 谱采集以及谱库检索，可在单次 LC-Q-LIT MS 分析中鉴定 240 种目标农药。通过使用 LC 保留时间、1 个 sMRM 全扫描转换和谱库检索，在 18 种不同食品中，10 ng/g 加标浓度下，单次 LC/MS 分析可鉴定出 240 种农药中的 75%-87%。使用 EPI 谱库检索的 LC-Q-LIT 与使用两个 MRM 转换的传统 LC-MS/MS 方法得到了相同的鉴定结果和可比的定量结果，在桃中检测到 1.2-49ng/g 的克百威、多菌灵、苯醚甲环唑、丙环唑或吡虫啉，在橙子中检测到多菌灵、乙霉威、特丁津和噻菌灵，在三文鱼中检测到特丁津，在人参中检测到唑菌胺酯；使用相同的 EPI 谱库，用 3 台 LC-Q-LIT 和 1 台 LC-四极飞行时间（Q-TOF）仪器筛选了受污染的西兰花、白菜和羽衣甘蓝。谱库检索鉴定出唑菌胺酯、咯菌腈、氟啶胺、吡虫啉、甲霜灵、螺虫乙酯、螺虫噻虫胺 A、D 和 J 以及螺虫乙酯。该方法在食品分析中的 LC-MS/MS 型靶向筛选中具有广泛的应用。
