Wong Jon W, Hennessy Michael K, Hayward Douglas G, Krynitsky Alexander J, Cassias Irene, Schenck Frank J
Center for Food Safety and Applied Nutrition, Office of Plant and Dairy Foods, HFS-336, U.S. Food and Drug Administration, 5100 Paint Branch Parkway, College Park, MD 20740-3835, USA.
J Agric Food Chem. 2007 Feb 21;55(4):1117-28. doi: 10.1021/jf062774q. Epub 2007 Jan 24.
A method was developed to determine organophosphorus pesticides (OPs) in dried ground ginseng root. Pesticides were extracted from the sample using acetonitrile/water saturated with salts, followed by solid-phase dispersive cleanup, and analyzed by capillary gas chromatography with electron ionization mass spectrometry in selective ion monitoring mode (GC-MS/SIM) and flame photometric detection (GC-FPD) in phosphorus mode. The detection limits for most of the pesticides were 0.025-0.05 microg/g using GC-FPD but were analyte-dependent for GC-MS/SIM, ranging from 0.005 to 0.50 microg/g. Quantitation was determined from 0.050 to 5.0 microg/g with r 2 > 0.99 for a majority of the pesticides using both detectors. Recovery studies were performed by fortifying the dried ground ginseng root samples to concentrations of 0.025, 0.1, and 1.0 microg/g, resulting in recoveries of >90% for most pesticides by GC-FPD. Lower (<70%) and higher (>120%) recoveries were most likely from complications of pesticide lability or volatility, matrix interference, or inefficient desorption from the solid-phase sorbents. There was difficulty in analyzing the ginseng samples for the OPs using GC-MS at the lower fortification levels for some of the OPs due to lack of confirmation. GC-FPD and GC-MS/SIM complement each other in detecting the OPs in dried ground ginseng root samples. This procedure was shown to be effective and was applied to the analysis of OPs in ginseng root samples. One particular sample, a ground and dried American ginseng (Panax quinquefolius) root sample, was found to contain diazinon quantified at approximately 25 microg/kg by external calibration using matrix-matched standards or standard addition using both detectors. The advantage of using both detectors is that confirmation can be achieved using GC-MS, whereas the use of a megabore column in GC-FPD can be used to quantitate some of the nonpolar OPs without the use of matrix-matched standards or standard addition.
开发了一种测定干人参根中有机磷农药（OPs）的方法。使用饱和盐的乙腈/水从样品中提取农药，随后进行固相分散净化，并通过在选择性离子监测模式下的毛细管气相色谱-电子电离质谱（GC-MS/SIM）和磷模式下的火焰光度检测（GC-FPD）进行分析。使用GC-FPD时，大多数农药的检测限为0.025 - 0.05微克/克，但GC-MS/SIM的检测限因分析物而异，范围为0.005至0.50微克/克。使用两种检测器时，大多数农药的定量范围为0.050至5.0微克/克，r² > 0.99。通过将干人参根样品强化至0.025、0.1和1.0微克/克的浓度进行回收率研究，使用GC-FPD时，大多数农药的回收率>90%。较低（<70%）和较高（>120%）的回收率最有可能是由于农药的不稳定性或挥发性、基质干扰或固相吸附剂上解吸效率低下等复杂情况导致的。对于某些OPs，在较低强化水平下使用GC-MS分析人参样品时，由于缺乏确证存在困难。GC-FPD和GC-MS/SIM在检测干人参根样品中的OPs方面相互补充。该方法被证明是有效的，并应用于人参根样品中OPs的分析。一个特定的样品，即磨碎并干燥的西洋参（Panax quinquefolius）根样品，通过使用基质匹配标准品的外标法或使用两种检测器的标准加入法，发现含有约25微克/千克的二嗪农。使用两种检测器的优点是可以使用GC-MS进行确证，而在GC-FPD中使用大口径柱可用于定量一些非极性OPs，而无需使用基质匹配标准品或标准加入法。
