Chen Ping, Hou Keyong, Hua Lei, Xie Yuanyuan, Zhao Wuduo, Chen Wendong, Chen Chuang, Li Haiyang
Dalian Institute of Chemical Physics, Chinese Academy of Sciences , Dalian 116023, People's Republic of China.
Anal Chem. 2014 Feb 4;86(3):1332-6. doi: 10.1021/ac403132k. Epub 2014 Jan 17.
The application of VUV lamp-based single photon ionization (SPI) was limited due to low photon energy and poor photon flux density. In this work, we designed a quasi-trapping chemical ionization (QT-CI) source with a commercial VUV 10.6 eV krypton lamp for time-of-flight mass spectrometry. The three electrode configuration ion source with RF voltage on the second electrode constitutes a quasi-trapping region, which has two features: accelerating the photoelectrons originated from the photoelectric effect with VUV light to trigger the chemical ionization through ion-molecule reaction and increasing the collisions between reactant ion O2(+) and analyte molecules to enhance the efficiency of chemical ionization. Compared to single SPI based on VUV krypton lamp, the QT-CI ion source not only apparently improved the sensitivity (e.g., 12-118 fold enhancement were achieved for 13 molecules, including aromatic hydrocarbon, chlorinated hydrocarbon, hydrogen sulfide, etc.) but also extended the range of ionizable molecules with ionization potential (IP) higher than 10.6 eV, such as propane, dichloroethane, and trichloromethane.
基于真空紫外（VUV）灯的单光子电离（SPI）技术由于光子能量低和光子通量密度差而受到限制。在本工作中，我们为飞行时间质谱仪设计了一种基于商用VUV 10.6 eV氪灯的准俘获化学电离（QT-CI）源。在第二个电极上施加射频电压的三电极配置离子源构成了一个准俘获区域，该区域具有两个特点：加速由VUV光的光电效应产生的光电子，通过离子-分子反应触发化学电离；增加反应物离子O2(+)与分析物分子之间碰撞，提高化学电离效率。与基于VUV氪灯的单SPI相比，QT-CI离子源不仅显著提高了灵敏度（例如，对于13种分子，包括芳烃、氯代烃、硫化氢等，灵敏度提高了12至118倍），还扩展了可电离分子的范围，这些分子的电离电位（IP）高于10.6 eV，如丙烷、二氯乙烷和三氯甲烷。
