气相色谱-串联质谱技术分析地质调查植物样品中持久性有机污染物的优势

对于复杂基质的样品,采用气相色谱法、气相色谱-质谱法( GC - MS)不能满足当前痕量水平分析的要求,串联质谱已发展成一种有机分析测试的成熟技术可应用于地质调查样品分析.本文建立了气相色谱-串联质谱技术( GC - MS - MS)分析植物样品中有机氯农药及多氯联苯的方法,通过对植物样品(圆白菜、菠菜、胡萝卜、橘子)分析,系统比较了GC- MS-MS与气相色谱-电子捕获检测器(GC-ECD)和气相色谱-选择离子-质谱( GC - SIS - MS)三种分析技术的检出限、定性定量分析结果,确认了分析方法的适用性.GC- MS-MS方法的检出限为0.03～0.29 ng/g,大部分化合物均低于GC -ECD的检出限,是GC - SIS -MS检出限的0.4倍.GC- MS-MS分析表明,圆白菜不含反式-氯丹,排除了GC-ECD的假阳性检出；检测胡萝卜等基质复杂、净化困难的样品,GC- MS-MS也表现出良好的定性定量能力；检出低含量水平样品菠菜含有0.26 ng/g六氯苯,而气相色谱未检出,表明GC- MS-MS显著提高了分析灵敏度,能够对样品中低含量的化合物进行准确定量.在三种分析技术中,GC- MS-MS在样品的准确定性、复杂基质样品分析灵敏度、低含量水平准确定量等方面都具有独特的优势,同时能够应用于复杂样品检测结果的确证.

The Technical Advantage of Using Gas Chromatography-Tandem Mass Spectrometry for Persistent Organic Pollutants Analysis in Plant Samples of Geological Survey

Tandem mass spectrometry has developed into a mature technology, applied to pesticides, food safety, environment, medicine and so on. Methods such as Gas Chromatography (GC) and Gas Chromatography-Mass Spectrometry (GC-MS) cannot meet the requirements of trace level analysis for complex samples. In this paper, the method of analysis organochlorine pesticides and polychlorinated biphenyls in plants by Gas Chromatography-Tandem Mass Spectrometry is described. According to the detection limits and qualitative and quantitative analysis of results by GC-MS-MS, Gas Chromatography-Electron Capture Detector (GC-ECD) and Gas Chromatography-Select Ion Storage-Mass Spectrometry (GC-SIS-MS), the applicability of the method GC-MS-MS was inspected through the detection of actual samples such as cabbage, spinach, carrots and oranges. The method detection limits (MDL) of GC-MS-MS were between 0.03 ng/g and 0.29 ng/g, and the MDL of the majority of compounds was lower than those by GC-ECD. The average MDL is 0.4 times lower than those by GC-SIS-MS. In this study, it was found that cabbage samples do not contain trans-chlordane analyzed by GC-MS-MS. This result eliminated the false positive detection by GC-ECD. GC-MS-MS also showed good qualitative and quantitative ability to analyze carrot samples with complex matrices, which was difficult to purify. The 0.03 ng/g HCB was detected in spinach by GC-MS-MS, which was not detected by GC-ECD. This indicates that the method of GC-MS-MS has higher sensitivity and can accurately measure trace compounds in the sample. Compared with the different results by various analysis technology including GC-ECD, GC-SIS-MS and GC-MS-MS, tandem mass spectrometry has the advantages of high sensitivity and accurate qualitative and quantitative analysis. This technology can reduce purification steps and improve analysis efficiency, which can be applied to verify the analytical results for complex samples.