建立了一种气相色谱(GC)与单光子电离-飞行时间质谱(SPI-TOFMS)联用(GC/SPI-TOFMS)的分析方法。首先,设计了一种双层套管的传输管用于连接GC与SPI—TOFMS,实现了GC与单光子电离离子源的无缝连接。在此基础上,以他一十五烷标准品和苯/甲苯/二甲苯的标准气为对象,对电离源的重要电压参数进行了优化,得到了纯净的分子离子峰,实现了对各类有机物的快速和准确定性。最后,将该方法用于分析柴油中的挥发性与半挥发性有机物,获得了柴油组分的二维GC×SPI—TOFMS谱图。不需要复杂的谱图解析和数据处理,根据谱图中离子的质荷比(m/z)归纳了柴油的主要成分,包括脂肪烃、芳香烃和含量很低的苯并吡咯等含氮化合物;根据色谱的保留时间将柴油中的同分异构体区分开来。结果表明GC/SPI—TOFMS法是一种简单、有效的分析方法,非常适于柴油及复杂环境样品等的分析表征。
A novel analytical method coupling gas chromatography (GC) with single photon ionization time-of-flight mass spectrometry (SPI-TOF MS) has been developed. First of all, a double-wall-tube transfer line was built to combine GC with SPI-TOF MS, which realized seam- less connection between GC and SPI ion source. Based on this, standard n-pentadecane and benzene/toluene/xylene standard gas mixtures were used to study important voltage parameters of the ion source. After the optimization of the ion source voltages, pure molecular ion peaks of the analytes were obtained in the mass spectra and qualitative analysis of different kinds of or- ganic compounds were eventually realized rapidly and accurately. At last, GC/SPI-TOF MS was applied to the characterization of volatile and semi-volatile organic compounds in diesel and two-dimensional spectra of GCxSPI-TOF MS were obtained. Without complicated spectra inter- pretation and data processing, volatile and semi-volatile organic compounds in diesel have been classified qualitatively by ion mass-to-charge ratio (m/z) in SPI mass spectra, including ali- phatic compounds, aromatic compounds and nitrogen-containing compounds with low concen- tration such as benzopyrroles. Isomeric compounds in diesel were separated and identified byretention times of chromatographic peaks. The results indicate method of GC/SPI-TOF MS is suitable for the characterization of diesel and environmental pollutants with easy operation and high that the proposed analytical complicated samples such as efficiency.