GC×GC Measurements of Atmospheric Aromatic Compounds near a Busy High-speed Road in Beijing
全二维气相色谱法测定北京交通干道大气中芳香烃

Comprehensive two-dimensional gas chromatography(GC×GC)is a powerful instrumental tool often used to analyze complex mixtures. An optimized GC×GC method had been applied to the quantitative analysis of aromatic compounds in air samples collected near a busy high-speed road in Beijing during the 2007 National Holidays. In the resulting GC×GC chromatograms, aromatic species were resolved from other compound classes and were grouped in a manner that facilitated identification and integration, showing more information of aromatic compounds compared to traditional one-dimensional GC. Totally more than 30 aromatic species were identified and quantified. The average concentrations of monocyclic aromatic compounds ranged from 0.75×10~(-9) to 24.64×10~(-9) C, with toluene having the highest concentration, followed by,m,p-xylene and ethylbenzene. The average concentrations of the measured polycyclic aromatic compounds ranged from 0.03×10~(-9) to 2.28 × 10~(-9) C. with naphthalene having the highest concentration, followed by 2-methyl-naphthalene and 4-methyl-1,1'-biphenyl.The four-ring and higher polycyclic aromatic compounds were not detectable in the gaseous samples. The levels of aromatic compounds were significantly influenced by meteorological parameters. Benzene and toluene were poorly correlated with higher aromatic compounds though the latter compounds were highly correlated among each other, suggesting that both were significantly influenced by sources other than vehicle exhaust and gasoline evaporation.