Use of humidified air in optimizing APCI-MS response in breath analysis

G. Zehentbauer, T. Krick, G. A. Reineccius

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36 Scopus citations


An atmospheric-pressure chemical ionization-mass spectrometer (APCI-MS) system was modified to introduce gaseous samples as well as to humidify sheath and auxiliary gases. Solutions of single odorants in pentane were evaporated inside a vessel in a dry environment (relative humidity 0-10%) and in a human-breath-like environment (relative humidity 88-98%) and subsequently analyzed in the positive ion mode. The results indicated that using dry nitrogen as sheath and auxiliary gases led to strong fragmentation of the molecules combined with a low sensitivity of detection. Humidification of both gases not only increased sensitivity but also resulted in the protonated molecular ion as the base peak in 5 of the 6 compounds studied (ethyl butyrate, 3-methyl-3-phenyl glycidic acid ethyl ester, γ-decalactone, (E)-2-hexenal, and cinnamic aldehyde). Only hexanal, which formed a cluster (m/z 183), did not have the protonated molecular ion as base peak. It was found that the humidity of the sample itself did not have any influence on sensitivity or fragmentation.

Original languageEnglish (US)
Pages (from-to)5389-5395
Number of pages7
JournalJournal of agricultural and food chemistry
Issue number11
StatePublished - Dec 12 2000


  • Aroma release
  • Flavor
  • Humidification


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