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采用膜进样-光电子磁场增强电离(MEPEI)/单光子电离(SPI)复合电离源飞行时间质谱(TOF-MS)在线分析水中醚类汽油添加剂:甲基叔丁基醚(MTBE)、乙基叔丁基醚(ETBE)、甲基叔戊基醚(TAME)和二异丙基醚(DIPE)。膜进样方式无需样品前处理,通过渗透蒸发实现液体样品在线富集;SPI电离碎片离子少,谱图简单,可利用分子离子进行快速的半定性分析;MEPEI产生样品分子碎片可精确定性同分异构体,从而克服直接进样时复杂基质中重叠峰解析的难题。在最优实验条件下:膜温度为60℃,膜厚度为50μm,膜面积为160 mm2,单个样品分析时间小于100 s。MTBE,ETBE,TAME和DIPE的检出限分别达到5.5,4.8,3.3和4.3μg/L。本方法成功应用于模拟地下水中MTBE类汽油添加剂的快速检测。
In-line analysis of ether gasoline additives in water: methyl tert-butyl ether (MTBE), ethyl (methyl methacrylate), methyl ethyl ether Tert-butyl ether (ETBE), methyl t-amyl ether (TAME) and diisopropyl ether (DIPE). Membrane injection method without sample pretreatment, liquid sample enrichment by pervaporation online; SPI ionization fragment ion less, simple spectroscopy, rapid semi-qualitative analysis of molecular ions can be used; MEPEI molecular sample fragments can be accurately defined with the same sub Isomers, thereby overcoming the problem of overlapping peaks resolution in complex matrices when directly injected. Under the optimal experimental conditions, the membrane temperature was 60 ℃, the membrane thickness was 50μm, the membrane area was 160 mm2, and the single sample analysis time was less than 100 s. The detection limits of MTBE, ETBE, TAME and DIPE reached 5.5, 4.8, 3.3 and 4.3 μg / L, respectively. The method has been successfully applied to simulate the rapid detection of MTBE gasoline additives in groundwater.