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Development of a new electron ionization/field ionization ion source for gas chromatography/time‐of‐flight mass spectrometry
Author(s) -
Miyamoto Kenji,
Fujimaki Susumu,
Ueda Yoshihisa
Publication year - 2009
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.4256
Subject(s) - chemistry , electron ionization , field desorption , mass spectrum , ion source , mass spectrometry , analytical chemistry (journal) , ion , ionization , time of flight mass spectrometry , thermal ionization mass spectrometry , direct electron ionization liquid chromatography–mass spectrometry interface , chemical ionization , chromatography , organic chemistry
We have developed a combined EI/FI source for gas chromatography/orthogonal acceleration time‐of‐flight mass spectrometry (GC/oaTOFMS). In general, EI (electron ionization) and FI (field ionization) mass spectra are complementary: the EI mass spectrum contains information about fragment ions, while the FI mass spectrum contains information about molecular ions. Thus, the comparative study of EI and FI mass spectra is useful for GC/MS analyses. Unlike the conventional ion sources for FI and EI measurements, the newly developed source can be used for both measurements without breaking the ion source vacuum or changing the ion source. Therefore, the combined EI/FI source is more preferable than the conventional EI or FI ion source from the viewpoint of the reliability of measurements and facility of operation. Using the combined EI/FI source, the complementarity between EI and FI mass spectra is demonstrated experimentally with n ‐hexadecane (100 pg): characteristic fragment ions for the n ‐alkane such as m/z 43, 57, 71, and 85 are obtained in the EI mass spectrum, while only the parent peak of m/z 226 (M + ) without any fragment ions is observed in the FI mass spectrum. Moreover, the field desorption (FD) measurement is also demonstrated with poly(ethylene glycol)s M 600 (10 ng) and M 1000 (15 ng). Signals of [M+H] + , [M+Na] + and [M+K] + are clearly detected in the FD mass spectra. Copyright © 2009 John Wiley & Sons, Ltd.