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采用QuEChERS前处理方法和在线凝胶过滤色谱-气相色谱-质谱(GPC-GC/MS)联用法对蔬菜水果样品中的25种有机氯、菊酯和杀螨剂等农药残留进行测定。首先用QuEChERS方法进行样品前处理,即乙腈提取,提取溶液经脱水后离心,用分散性吸附剂去除离心提取液中的干扰基质(如脂肪酸和色素等),然后直接进行在线GPC-GC/MS分析。GPC-GC/MS系统中的GPC能弥补QuEChERS方法去除干扰物质不彻底的问题,从而降低了分析背景,改善了峰形,提高了分析结果的准确性和相关质谱图的匹配性。在加标0.01 mg/kg情况下,3种样品(菠菜、黄瓜和苹果)的回收率均在80%~120%之间,相对标准偏差(RSD)均小于20%。
The determination of 25 pesticide residues such as organochlorine, pyrethrins and acaricide in vegetable and fruit samples was carried out by using QuEChERS pretreatment method and on-line gel filtration chromatography-gas chromatography-mass spectrometry (GPC-GC / MS). First, the samples were pre-treated with QuEChERS method, that is, acetonitrile extraction, the extract solution was dehydrated and centrifuged, and the dispersive adsorbent was used to remove interfering substrates (such as fatty acids and pigments) in the centrifugal extract and then directly performed on-line GPC-GC / MS analysis. The GPC in GC-MS / MS system can make up for the incomplete QuEChERS method to remove interfering substances, which reduces the background of analysis and improves the peak shape, and improves the accuracy of the analytical results and the matching of related spectra. The recoveries of three samples (spinach, cucumber and apple) ranged from 80% to 120% and the relative standard deviations (RSDs) were all less than 20% at the spiked level of 0.01 mg / kg.