Determination of a Wide Range of Volatile Organic Compounds in Ambient Air Using Multisorbent Adsorption/Thermal Desorption and Gas Chromatography/Mass Spectrometry

Abstract

Adsorption/thermal desorption with multisorbent airsampling cartridges was developed for the determination of 87 method analytes including halogenated alkanes, halogenated alkenes, ethers, alcohols, nitriles, esters, ketones, aromatics, a disulfide, and a furan. The volatilities of the compounds ranged from that of dichlorofluoromethane (CFC12) to that of 1,2,3-trichlorobenzene. The eight most volatile compounds were determined using a 1.5-L air sample and a sample cartridge containing 50 mg of Carbotrap B and 280 mg of Carboxen 1000; the remaining 79 compounds were determined using a 5-L air sample and a cartridge containing 180 mg of Carbotrap B and 70 mg of Carboxen 1000. Analysis and detection were by gas chromatography/mass spectrometry. The minimum detectable level (MDL) concentration values ranged from 0.01 parts per billion by volume (ppbv) for chlorobenzene to 0.4 ppbv for bromomethane; most of the MDL values were in the range 0.02-0.06 ppbv. No breakthrough was detected with the prescribed sample volumes. Analyte stability on the cartridges was very good. Excellent recoveries were obtained with independent check standards. Travel spike recoveries ranged from 90 to 110% for 72 of the 87 compounds. The recoveries were less than 70% for bromomethane and chloroethene and for a few compounds such as methyl acetate that are subject to losses by hydrolysis; the lowest travel spike recovery was obtained for bromomethane (62%). Blank values for all compounds were either below detection or very low. Ambient atmospheric sampling was conducted in New Jersey from April to December, 1997. Three sites characterized by low, moderate, and high densities of urbanization/traffic were sampled. The median detected concentrations of the compounds were either similar at all three sites (as with the chlorofluorocarbon compounds) or increased with the density of urbanization/traffic (as with dichloromethane, MTBE, benzene, and toluene). For toluene, the median detected concentrations were 0.23, 0.42, and 0.70 ppbv at the three sites. Analytical precision was measured using duplicate sampling. As ex-

Presence and Partitioning Behavior of Polyfluorinated Iodine Alkanes in Environmental Matrices around a Fluorochemical Manufacturing Plant: Another Possible Source for Perfluorinated Carboxylic Acids?

“…Stoichiometric model (33) showed that the calculated vapor pressures ranged from 0.122 (PFDoI) to 20.4 Torr (PFHxI) for the FIAs and 0.095 (PFDoHI) to 2.9 Torr (PFOHI) for the FTIs, which were almost the same as or even higher than the calculated values for FTOHs (0.008 Torr (10:2 FTOH) to 9.94 Torr (4:2 FTOH)) and measured results (1.08 Torr (10:2 FTOH) to 7.44 Torr (4:2 FTOH)) (29). It is widely accepted that chemicals with vapor pressures above 0.1 Torr are usually classified as volatile organic compounds (VOCs) (34) and consequently most of the PFIs can also be considered as neutral volatile fluorinated substances, which would mostly be evaporated from soil or directly emitted into the atmosphere under ambient conditions. However, heavier homologues of the FIAs and FTIs have relatively higher predicted octanol-air partition coefficient (Log K oa , e.g., 4.70 for PFDoHI and 3.23 for PFHxHI) and coefficient of fraction sorbed to atmospheric particulates (Log phi, e.g., -4.80 for PFDoHI and -6.90 for PFHxHI) (33).…”

Trace determination of airborne polyfluorinated iodine alkanes using multisorbent thermal desorption/gas chromatography/high resolution mass spectrometry

“…The QA/QC utilized was similar to that previous reported with little modification [27]. In brief, lot blanks, trip blanks, field blanks, travel spikes, laboratory blanks, and laboratory check standards were conducted.…”

“…Moreover, many important perfluorinated iodine alkanes and telomer homologues were not included in the mentioned work, and thus a robust analytical method is still unavailable for this purpose. Adsorption/thermal desorption method is generally recognized and widely used as an effective technique for the analysis of a wide range of hazardous air pollutants [26][27][28][29][30] that are classified as volatile organic compounds (VOCs) and usually have vapor pressures above 0.1 Torr [27]. Compared with typical solvent-based extraction and injection scenarios, thermal desorption method requires less pretreatment procedures, reduces mass loss before quantification and enhances detection sensitivity by whole sample injection into the analytical instrument.…”

Comparison of Air Pollution by VOCs Inside the Cabins of New Vehicles

“…Sampling of duplicate samples was performed simultaneously onto two pairs of solid sorbents, connected in parallel to the air pumps. The precision of the sampling method was designated as relative standard deviation (%RSD) for each pair of duplicate samples, and was considered acceptable where RSD was lower than 20% (Pankow et al, 1998;EPA, 1999). The concentrations of target compounds in field blank samples were lower than 5% of the target compounds in real samples.…”