title: Determination of isoprene in human expired breath using solid-phase microextraction and gas chromatography-mass spectrometry.
abstract: An analytical method for determination of isoprene in expired breath as a marker of body cholesterol synthesis was developed with a special emphasis on breath sampling. Patients were breathing controlled air using respiratory masks for 2 min (washout period) and then their expired breath was collected in 8-1 Tedlar bags. The bags were heated to 40 degrees C and the solid-phase microextraction fiber Carboxen-polydimethylsiloxane 75 microm was inserted through the septum. Extraction time was 10 min. Analytes were desorbed in the GC injector for 2 min at 270 degrees C. Analyses were performed on a Q-PLOT column and fragment ions 68, 67 and 53 were quantified. The concentration range was 1-40 nmol/l, limit of detection was 0.25 nmol/l, the calibration curve was linear. Precision, expressed as RSD, was 5.5-12.5%. These tests are non-invasive, feasible and relatively inexpensive.
authors.affiliation: Medical Faculty, Charles University, Hradec Králové, Czech Republic. rhyspler@lfhk.cuni.cz
authors.forename: R
authors.initials: R
authors.lastname: Hyspler
authors.forename: S
authors.initials: S
authors.lastname: Crhová
authors.forename: J
authors.initials: J
authors.lastname: Gasparic
authors.forename: Z
authors.initials: Z
authors.lastname: Zadák
authors.forename: M
authors.initials: M
authors.lastname: Cízková
authors.forename: V
authors.initials: V
authors.lastname: Balasová
mesh_terms: D001944:Breath Tests / Q000379:methods*; D002070:Butadienes / Q000032:analysis*; D002138:Calibration; D002245:Carbon Dioxide / Q000737:chemistry; D004355:Drug Stability; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D045782:Hemiterpenes; D006801:Humans; D006813:Humidity; D010420:Pentanes; D011786:Quality Control; D015203:Reproducibility of Results; D013696:Temperature; D013997:Time Factors
chemical_list: D002070:Butadienes; D045782:Hemiterpenes; D010420:Pentanes; C005059:isoprene; D002245:Carbon Dioxide