Abstract
Exhaust gases from internal combustion engines are the main source of urban air pollution. Quantification of Polycyclic aromatic hydrocarbons (PAHs) in the exhaust gases is needed for emissions monitoring, enforcement, development, and testing of control technologies. The objective was to develop quantification of gaseous naphthalene in diesel engine exhaust based on diffusion-controlled extraction onto a retracted solid-phase microextraction (SPME) fiber coating and analysis on gas chromatography-mass spectrometry (GC-MS). Extraction of naphthalene with retracted fibers followed Fick’s law of diffusion. Extracted mass of naphthalene was proportional to Cg, t, Dg, T and inversely proportional to Z. Method detection limit (p = 0.95) was 11.5 ppb (0.06 mg·m−3) at t = 9 h, Z = 10 mm and T = 40 °C, respectively. It was found that the % mass extracted of naphthalene by SPME needle assembly depended on the type of fiber. Storage time at different temperatures did not affect analyte losses extracted by polydimethylsiloxane (PDMS) 100 µm fiber. The developed method was tested on exhaust gases from idling pickup truck and tractor, and compared side-by-side with a direct injection of sampled exhaust gas method. Time-weighted average (TWA) concentrations of naphthalene in exhaust gases from idling pickup truck and a tractor ranged from 0.08 to 0.3 mg·m−3 (15.3–53.7 ppb).
Highlights
Analysis of variance (ANOVA) showed no effect on mass extracted by randomly selected PA and DVB fiber coating
The following conclusions can be made about the effects of sampling parameters on the solid-phase microextraction (SPME) method: i
ANOVA showed no effect on mass extracted by randomly selected PA and DVB fiber coating, while randomly selected PDMS fibers extract significantly different masses of analytes
Summary
Air pollution causes disruption of ecosystems and creates significant economic and social cost to society. Polycyclic aromatic hydrocarbons (PAHs) are one of the main toxic groups of ambient air pollutants due to their mutagenic and carcinogenic properties. Protection Agency’s (EPA) list of carcinogenicity or genotoxicity includes 16 priority PAHs [1]: naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benz[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, dibenz[a,h]anthracene, benzo[g,h,i]perylene, indeno[1,2,3-c,d]pyrene. Naphthalene is a PAH with the simplest 2-ring structure, and is often used as a model and target compound studied in this group. Naphthalene is classified as a “possible” human carcinogen [2]
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