title: Development and validation of a method for air-quality and nuisance odors monitoring of volatile organic compounds using multi-sorbent adsorption and gas chromatography/mass spectrometry thermal desorption system.
abstract: An analytical method based on thermal desorption (TD) coupled to gas chromatography (GC) and mass spectrometry detection (MS) has been developed and validated for the determination of a wide range of odor nuisance and air-quality volatile organic compounds (VOC) in air. New generation isocyanates, isocyanato- and isothiocyanatocyclohexane, have been included for the first time as target compounds due to their high occurrence in air samples. A dynamic air sampling method to trap gas and vapor on multi-sorbent tubes using portable pump equipment has been also developed. Sorbent tubes were filled with Carbotrap (70mg), Carbopack X (100mg) and Carboxen-569 (90mg). Validation of the TD-GC-MS method showed good selectivity, sensibility and precision according to Compendium Method TO-17 (US Environment Protection Agency) criteria. Limits of detection (signal-to-noise=3, ng in tube) ranges were 0.004-0.03ng (alcanes), 0.001-0.1ng (aromatics), 0.03-14ng (aldehydes), 0.003-7ng (alcohols), 0.003-0.04ng (chlorides), 0.02-0.5ng (esters), 0.002-0.1ng (ketones), 0.01-0.53ng (terpenes), 14-97ng (amides), 0.2-10ng (isocyanates) and 0.001ng (carbon disulfide). The linear dynamic range was over 3-5 orders of magnitude, depending of the VOC. TD-GC-MS analysis was reproducible, with relative standard deviation (n=5) within 20%. VOCs breakthrough examination showed no significant losses when about 2000ng standard was prepared. In order to evaluate the performance of the developed method on real samples, several industrial and urban air samples were analysed. VOCs were found to be stable on the sorbent tubes for at least 1 week when stored at 4 degrees C.
authors.affiliation: Laboratori del Centre de Medi Ambient (LCMA), Universitat Politècnica de Catalunya (UPC), Avda. Diagonal 647, 08028 Barcelona, Spain. sandraribes@yahoo.es
authors.forename: Alejandra
authors.initials: A
authors.lastname: Ribes
authors.forename: Guillem
authors.initials: G
authors.lastname: Carrera
authors.forename: Eva
authors.initials: E
authors.lastname: Gallego
authors.forename: Xavier
authors.initials: X
authors.lastname: Roca
authors.forename: M A José
authors.initials: MA
authors.lastname: Berenguer
authors.forename: Xavier
authors.initials: X
authors.lastname: Guardino
mesh_terms: D000327:Adsorption; D000393:Air Pollutants / Q000032:analysis*; D016902:Air Pollution, Indoor / Q000032:analysis; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D009812:Odorants / Q000032:analysis*; D009930:Organic Chemicals / Q000032:analysis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014835:Volatilization
chemical_list: D000393:Air Pollutants; D009930:Organic Chemicals