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在无放射性辉光放电离子源内,采用不同试剂气体进行放电,为质子转移反应质谱(PTR-MS)新增了强度在105 cps量级的3种反应离子NH4+,NO+和O2+,纯度大于95%;测试了这3种反应离子的离子-分子反应特征.采用H3O+,NH4+,NO+和O2+等4种反应离子对同分异构体丙醛/丙酮进行检测发现,H3O+和NH 4+均不能区分的丙醛/丙酮可采用NO+或O 2+进行区分.结果表明,增加反应离子不仅使PTR-MS的可检测有机物范围不再局限于质子亲和势(PA)大于H2O的有机物,还提高了PTR-MS区分同分异构体的能力.
In the non-radioactive glow discharge ion source, different reagent gases were used for discharging. Three kinds of reactive ions NH4 +, NO + and O2 + with intensities of 105 cps were added for PTR-MS, the purity was more than 95% The ion-molecular reaction characteristics of the three reactive ions were tested.The isomers of propionaldehyde / acetone were detected by four kinds of reactive ions, such as H3O +, NH4 +, NO + and O2 +, and found that neither H3O + nor NH4 + Of propionaldehyde / acetone can be distinguished by NO + or O 2 + .The results show that the addition of reactive ions not only limits the range of detectable organics of PTR-MS to organic matter with proton affinity (PA) greater than H 2 O but also increases The ability of PTR-MS to differentiate isomers.