Norwegian Institute for Agricultural and Environmental Research, Plant Health and Plant Protection Division, Pesticide Chemistry Section, Høgskoleveien 7, N-1432 As, Norway.
J Chromatogr A. 2010 Mar 26;1217(13):2056-64. doi: 10.1016/j.chroma.2010.01.022. Epub 2010 Feb 2.
The gas chromatography mass spectrometry (GC-MS) deconvolution reporting software (DRS) from Agilent Technologies has been evaluated for its ability as a screening tool to detect a large number of pesticides in incurred and fortified samples extracted with acetone/dichloromethane/light petroleum (Mini-Luke method). The detection of pesticides is based on fixed retention times using retention time locking (RTL) and full scan mass spectral comparison with a partly customer built automated mass spectral deconvolution and identification system (AMDIS) database. The GC-MS was equipped with a programmable temperature vaporising (PTV) injector system which enables more sample to be injected. In a blind study of 52 real samples a total number of 158 incurred pesticides were found. In addition to the 85 pesticides found by manual interpretation of GC-NPD/ECD chromatograms, the DRS revealed 73 more pesticides (+46%). The DRS system also shows its potential to discover pesticides which are normally not searched for (EPN in long beans from Thailand). A spiking experiment was performed to blank matrices of apple, orange and lettuce with 177 different pesticides at concentration levels 0.02 and 0.1 mg/kg. The samples were analysed on GC-MS full scan and the AMDIS match factor was used as a mass spectral quality criterion. The threshold level of the AMDIS match factor was set at 20 to eliminate most of the false positives. AMDIS match factors from 20 up to 69 are regarded only as indication of a positive hit and must be followed by manual interpretation. Pesticides giving AMDIS match factors at > or = 70 are regarded as identified. To simplify and decrease the large amount of data generated at each concentration level, the AMDIS match factors > or = 20 was averaged (mean AMF) for each pesticide including the commodities and their replicates. Among 177 different pesticides spiked at 0.02 and 0.1 mg/kg level, the percentage of mean AMF values > or = 70 were 23% and 80%, respectively. For 531 individual detections of pesticides (177 pesticides x 3 replicates) giving AMDIS match factor 20 in apple, orange and lettuce, the detection rates at 0.02 mg/kg were 71%, 63% and 72%, respectively. For the 0.1 mg/kg level the detection rates were 89%, 85% and 89%, respectively. In real samples some manual interpretation must be performed in addition. However, screening by GC-MS/DRS is about 5-10 times faster compared to screening with GC-NPD/ECD because the time used for manual interpretation is much shorter and there is no need for re-injection on GC-MS for the identification of suspect peaks found on GC-NPD/ECD.
Agilent 科技公司的气相色谱-质谱（GC-MS）解卷积报告软件（DRS）已经过评估，用于作为一种筛选工具，以检测用丙酮/二氯甲烷/轻质石油（Mini-Luke 方法）提取的实际和添加样品中大量农药。农药的检测是基于使用保留时间锁定（RTL）的固定保留时间和与部分客户构建的自动化质谱解卷积和识别系统（AMDIS）数据库的全扫描质谱比较。GC-MS 配备了可编程温度汽化（PTV）进样系统，可实现更多样品的进样。在对 52 个实际样品的盲法研究中，发现了总共 158 种实际存在的农药。除了通过手动解释 GC-NPD/ECD 色谱图发现的 85 种农药外，DRS 还发现了 73 种以上的农药（+46%）。DRS 系统还显示了发现通常不搜索的农药（泰国豇豆中的 EPN）的潜力。在苹果、橙子和生菜的空白基质中，用浓度为 0.02 和 0.1 mg/kg 的 177 种不同农药进行了加标实验。对样品进行 GC-MS 全扫描分析，并使用 AMDIS 匹配因子作为质谱质量标准。将 AMDIS 匹配因子的阈值设置为 20，以消除大多数假阳性。AMDIS 匹配因子从 20 到 69 仅被视为阳性命中的指示，必须随后进行手动解释。匹配因子大于或等于 70 的农药被视为已识别。为了简化并减少每个浓度水平产生的大量数据，对每个农药（包括商品及其重复）的 AMDIS 匹配因子大于或等于 20 的平均值（平均 AMF）进行了平均。在 0.02 和 0.1 mg/kg 水平下添加的 177 种不同农药中，平均 AMF 值大于或等于 70%的百分比分别为 23%和 80%。在苹果、橙子和生菜中，对 AMDIS 匹配因子为 20 的 531 个农药的单个检测，在 0.02 mg/kg 水平的检测率分别为 71%、63%和 72%。在 0.1 mg/kg 水平，检测率分别为 89%、85%和 89%。在实际样品中，还必须进行一些手动解释。然而，与使用 GC-NPD/ECD 进行筛选相比，GC-MS/DRS 筛选的速度大约快 5-10 倍，因为手动解释所花费的时间要短得多，并且对于在 GC-NPD/ECD 上发现的可疑峰，无需在 GC-MS 上重新进样进行识别。
