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A low‐pressure penning ion source for volatile organic compounds
Author(s) -
Kohler M.,
Schlunegger U. P.
Publication year - 1993
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.1290071211
Subject(s) - chemistry , ion , ion source , analytical chemistry (journal) , mass spectrum , discharge pressure , spectral line , electron ionization , mass spectrometry , atomic physics , chromatography , organic chemistry , ionization , mechanical engineering , physics , astronomy , engineering , gas compressor
A Penning ion source for volatile organic compounds is described. Design, operating conditions, and properties of the ions generated are reported. The source operates at pressures ranging from 10 −5 to 10 −3 mbar; a sensitivity of 1.4 × 10 −4 A/mbar is achieved. Mass spectra of 4‐methyl‐2‐pentanone, ethyl benzoatc, dimethyl sulfoxide, trichlorofluoromethane and 1,1,2‐trichlorotrifluoroethane obtained at low discharge currents are almost identical with their corresponding electron impact spectra at 70 eV. Two different discharge modes, depending on pressure, were found. The average energy of the ions is proportional to the potential of the ion source (〈 E 〉 = 0.64 U , energy given in eV). Multiply charged Ar ions, Ar n + , up to n = 4, have been observed.