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报道了自行研制的质子转移反应质谱的基本结构和性能。利用水蒸气辉光放电产生了反应离子H3O+,以合成空气为反应气体,测量了H3O+与合成空气中的水反应产生的团簇离子H3O+(H2O)n的质谱。实验发现,当漂移管电场与分子密度比值为144Td时,增加的离子能量可以阻止团簇离子H3O+(H2O)n的形成,质谱观察到的离子主要是H3O+,其纯度可达99%以上,这时H3O+与有机物分子如甲苯的质子转移反应的产物离子也呈单一形式,团簇离子得到很好地抑制。根据离子强度和离子反应时间等参数,获得了PTR-MS目前的检出限为10-8(V/V)。利用PTR-MS对标准浓度甲苯及其稀释气体进行检测,表明PTR-MS在线定量检测准确性良好,线性动态范围跨越3个数量级,能够应用于大气中痕量挥发性有机物的实时在线测量。
The basic structure and properties of proton transfer reaction mass spectrometry The water vapor glow discharge was used to generate the reaction ion H3O +. The synthetic air was used as the reaction gas to measure the mass spectrum of the cluster ions H3O + (H2O) n generated by the reaction between H3O + and the water in the synthesis air. It was found that when the ratio of electric field to molecular density of drift tube is 144Td, the increased ion energy can prevent the formation of cluster ions H3O + (H2O) n. The observed ions in mass spectrometry are mainly H3O + with the purity of over 99% When H3O + and organic molecules such as toluene proton transfer reaction product ions were also a single form, the cluster ions are well inhibited. The current detection limit of PTR-MS was 10-8 (V / V) based on the ionic strength and ion reaction time. The detection of standard concentrations of toluene and its diluent gas using PTR-MS showed that on-line quantitative detection of PTR-MS with good linearity over 3 orders of magnitude could be applied to real-time on-line measurement of trace amounts of volatile organic compounds in the atmosphere.