title: Atmospheric pressure chemical ionization mass spectrometry of pyridine and isoprene: potential breath exposure and disease biomarkers.
abstract: Volatile organic compounds (VOCs) in exhaled human breath can serve as potential disease-specific and exposure biomarkers and therefore can reveal information about a subject's health and environment. Pyridine, a VOC marker for exposure to tobacco smoke, and isoprene, a liver disease biomarker, were studied using atmospheric pressure chemical ionization mass spectrometry (APCI-MS). While both molecules could be detected in low-ppb levels, interactions of the ionized analytes with their neutral forms and ambient air led to unusual ion/molecule chemistry. The result was a highly dynamic system and a nonlinear response to changes in analyte concentration. Increased presence of ambient water was found to greatly enhance the detection limit of pyridine and only slightly decrease that of isoprene. APCI-MS is shown to be a promising analytical tool in breath analysis with good detection limits, but its application requires a better understanding of the ion/molecule chemistry that may affect VOC quantification from a chemically complex system such as human breath.
authors.affiliation: Department of Chemistry, Centre for Research in Mass Spectrometry-CRMS, York University, Toronto, Ontario M3J 1P3, Canada.
authors.forename: Vitaliy
authors.initials: V
authors.lastname: Kapishon
authors.forename: Gregory K
authors.initials: GK
authors.lastname: Koyanagi
authors.forename: Voislav
authors.initials: V
authors.lastname: Blagojevic
authors.forename: Diethard K
authors.initials: DK
authors.lastname: Bohme
mesh_terms: D001274:Atmospheric Pressure; D015415:Biomarkers / Q000032:analysis; D001944:Breath Tests / Q000379:methods*; D002070:Butadienes / Q000032:analysis*; D018876:Environmental Illness / Q000175:diagnosis* / Q000378:metabolism; D045853:Exhalation; D005740:Gases / Q000737:chemistry*; D045782:Hemiterpenes / Q000032:analysis*; D006801:Humans; D013058:Mass Spectrometry / Q000379:methods*; D010420:Pentanes / Q000032:analysis*; D011725:Pyridines / Q000032:analysis*; D055549:Volatile Organic Compounds / Q000032:analysis
chemical_list: D015415:Biomarkers; D002070:Butadienes; D005740:Gases; D045782:Hemiterpenes; D010420:Pentanes; D011725:Pyridines; D055549:Volatile Organic Compounds; C005059:isoprene; C023666:pyridine