Direct analysis of saturated hydrocarbons using glow discharge plasma ionization source for mass spectrometry
Direct analysis of saturated hydrocarbons using glow discharge plasma ionization source for mass spectrometry
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DOI：
10.1016/j.talanta.2019.05.115
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发表时间：
2019-11-01
期刊：
影响因子：
6.1
通讯作者：
Wagatsuma, Kazuaki
中科院分区：
文献类型：
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作者：
Nunome, Yoko;Kodama, Kenji;Wagatsuma, Kazuaki
基于环境空气辉光放电等离子体的电离源由脉冲直流电压驱动，用于软等离子体电离（SPI）。这项工作的新颖之处在于，与分析物种类（M）相关的分子离子[M + 13](+)（可能通过多种氧化反应形成）在几千帕压力的空气等离子体中能够作为基峰被主要检测到，且几乎没有或仅有很少的碎片化。独特的离子[M + 13](+)被归为氧化产物[M + O - 3H](+)，通过使用氘代溶剂，其被确认为氘代离子[M + O - 3D](+)（[M + 10](+)）。电离反应表明，产物离子[M + O - 3H](+)可能源于M与O₂(+)的氢负离子抽取反应、[M - H](+)的脱氢反应，以及随后[M - 3H](+)与O₃的氧化反应。还测量了正构烷烃混合物以评估该系统中的分子间相互作用。检测限（LOD）在0.126 - 1.68 ppmv范围内，在最低浓度下重复性的相对标准偏差（RSD）约为10.0%。据我们所知，这是首次报道表明饱和烃的光谱模式可以在没有任何复杂碎片化的情况下直接测定。
The ionization source based on glow discharge plasma using ambient air is driven by a pulsed direct-current voltage for soft plasma ionization (SPI). The novelty of this work is that molecular ions [M+ 13](+) related to the analyte species (M), which may be formed by numerous oxidation, can be dominantly detected as a base peak with little or no fragmentation of them in an air plasma at a pressure of several kPa. The unique ion [M+ 13](+) was assigned to the oxidation product, [M+ O- 3H](+), which was confirmed as a deuterated ion [M+ O- 3D](+) ([M+ 10](+)) by using a deuterated solvent. The ionization reactions were suggested that the product ion [M+ O- 311](+) may arise from hydride abstraction reaction of M with O-2(+), dehydrogenation reaction of [M- H](+). and subsequently oxidation reaction of [M- 3F1](+) with O-3. n-Alkane mixtures was also measured to evaluate the intermolecular interaction in this system. The limits of detection (LOD) were in the range of 0.126-1.68 ppmv and the relative standard deviation (RSD) for repeatability was approximately 10.0% at the lowest concentration. To our knowledge, this is the first report demonstrating that the spectrum pattern of saturated hydrocarbons could be directly determined without any complicated fragmentation.