title: Solid-phase microextraction and the human fecal VOC metabolome.
abstract: The diagnostic potential and health implications of volatile organic compounds (VOCs) present in human feces has begun to receive considerable attention. Headspace solid-phase microextraction (SPME) has greatly facilitated the isolation and analysis of VOCs from human feces. Pioneering human fecal VOC metabolomic investigations have utilized a single SPME fiber type for analyte extraction and analysis. However, we hypothesized that the multifarious nature of metabolites present in human feces dictates the use of several diverse SPME fiber coatings for more comprehensive metabolomic coverage. We report here an evaluation of eight different commercially available SPME fibers, in combination with both GC-MS and GC-FID, and identify the 50/30 µm CAR-DVB-PDMS, 85 µm CAR-PDMS, 65 µm DVB-PDMS, 7 µm PDMS, and 60 µm PEG SPME fibers as a minimal set of fibers appropriate for human fecal VOC metabolomics, collectively isolating approximately 90% of the total metabolites obtained when using all eight fibers. We also evaluate the effect of extraction duration on metabolite isolation and illustrate that ex vivo enteric microbial fermentation has no effect on metabolite composition during prolonged extractions if the SPME is performed as described herein.
authors.affiliation: Department of Chemistry and Biochemistry, George Mason University, Manassas, Virginia, United States of America.
authors.forename: Emma
authors.initials: E
authors.lastname: Dixon
authors.forename: Cynthia
authors.initials: C
authors.lastname: Clubb
authors.forename: Sara
authors.initials: S
authors.lastname: Pittman
authors.forename: Larry
authors.initials: L
authors.lastname: Ammann
authors.forename: Zeehasham
authors.initials: Z
authors.lastname: Rasheed
authors.forename: Nazia
authors.initials: N
authors.lastname: Kazmi
authors.forename: Ali
authors.initials: A
authors.lastname: Keshavarzian
authors.forename: Pat
authors.initials: P
authors.lastname: Gillevet
authors.forename: Huzefa
authors.initials: H
authors.lastname: Rangwala
authors.forename: Robin D
authors.initials: RD
authors.lastname: Couch
mesh_terms: D005243:Feces / Q000737:chemistry*; D005410:Flame Ionization; D008401:Gas Chromatography-Mass Spectrometry; D006358:Hot Temperature; D006801:Humans; D055442:Metabolome; D012015:Reference Standards; D052617:Solid Phase Microextraction / Q000379:methods*; D013242:Sterilization; D013997:Time Factors; D055549:Volatile Organic Compounds / Q000032:analysis*
chemical_list: D055549:Volatile Organic Compounds