Photoionization-Generated Dibromomethane Cation Chemical Ionization Source for Time-of-Flight Mass Spectrometry and Its Application on Sensitive Detection of Volatile Sulfur Compounds.
Soft ionization mass spectrometry is one of the key techniques for rapid detection of trace volatile organic compounds. In this work, a novel photoionization-generated dibromomethane cation chemical ionization (PDCI) source has been developed for time-of-flight mass spectrometry (TOFMS). Using a commercial VUV lamp, a stable flux of CH2Br2(+) was generated with 1000 ppmv dibromomethane (CH2Br2) as the reagent gas, and the analytes were further ionized by reaction with CH2Br2(+) cation via charge transfer and ion association. Five typical volatile sulfur compounds (VSCs) were chosen to evaluate the performance of the new ion source. The limits of detection (LOD), 0.01 ppbv for dimethyl sulfide and allyl methyl sulfide, 0.05 ppbv for carbon disulfide and methanthiol, and 0.2 ppbv for hydrogen sulfide were obtained. Compared to direct single photon ionization (SPI), the PDCI has two distinctive advantages: first, the signal intensities were greatly enhanced, for example more than 10-fold for CH3SH and CS2; second, H2S could be measured in PDCI by formation [H2S + CH2Br2](+) adduct ion and easy to recognize. Moreover, the rapid analytical capacity of this ion source was demonstrated by analysis of trace VSCs in breath gases of healthy volunteers and sewer gases.
Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences , 457 Zhongshan Road, Dalian, 116023, People's Republic of China.|Graduate University of Chinese Academy of Sciences , 19 Yuquan Road, Beijing, 100039, People's Republic of China.
Jichun
J
Jiang
Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences , 457 Zhongshan Road, Dalian, 116023, People's Republic of China.|Graduate University of Chinese Academy of Sciences , 19 Yuquan Road, Beijing, 100039, People's Republic of China.
Yan
Y
Wang
Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences , 457 Zhongshan Road, Dalian, 116023, People's Republic of China.
Keyong
K
Hou
Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences , 457 Zhongshan Road, Dalian, 116023, People's Republic of China.
Lei
L
Hua
Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences , 457 Zhongshan Road, Dalian, 116023, People's Republic of China.
Ping
P
Chen
Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences , 457 Zhongshan Road, Dalian, 116023, People's Republic of China.|Graduate University of Chinese Academy of Sciences , 19 Yuquan Road, Beijing, 100039, People's Republic of China.
Wei
W
Liu
Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences , 457 Zhongshan Road, Dalian, 116023, People's Republic of China.
Yuanyuan
Y
Xie
Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences , 457 Zhongshan Road, Dalian, 116023, People's Republic of China.
Haiyang
H
Li
D057230:Limit of Detection; D013058:Mass Spectrometry / Q000379:methods*; D013440:Sulfides / Q000032:analysis*; D055549:Volatile Organic Compounds / Q000032:analysis*
D013440:Sulfides; D055549:Volatile Organic Compounds