Comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC×GC-TOFMS) is commercially available in the 1990s, with the characteristics of large peak capacity, high resolution, high sensitivity, etc. However, its application to the petroleum and geological analyses is just emerging in China and overseas. In this research, the analytical method for petroleum aromatic fraction using GC×GC-TOFMS is set up, via the choice of the column system and optimization of setting parameters, such as temperature programming, modulation time, hot pulse time, flow rate of carrier gas, data acquisition rate and data processing. The results indicate that different polar compounds of aromatic fraction distribute as bands on structured GC×GC chromatogram. Within each band, homologous compounds appear as a roof-tile structure based on the number of substituent residues. The aromatic compounds are identified and characterized according to the GC×GC chromatogram and mass spectra. According to the polarity and the number of rings, aromatic compounds are spatially present on one chromatogram, which directly reflects the distribution characteristics of complex compounds of aromatic hydrocarbons. In addition, quantitative analysis is favored as some overlapped peaks on traditional GC-MS chromatogram have been separated completely on GC×GC. Some heterocyclic atom aromatic compounds at trace level can be clearly identified using this method, for polarity differences from other interfered aromatic compounds. The development of this method and chromatogram recognition offer petroleum geologists a practical example for the application performance of GC×GC-TOFMS. comprehensive two-dimensional gas chromatography, time-of-flight mass spectrometry, aromatic compounds, heterocyclic compounds, petroleum geological experiments Citation: Wang H T, Weng N, Zhang S C, et al. Identification of petroleum aromatic fraction by comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry.The aromatic hydrocarbon is one of the most important fractions both in source rocks and petroleum, and it consists of hundreds of types of compounds with abundant geochemistry information. The ratios of peak intensity of a few aromatic hydrocarbons to that of phenanthrene illustrate the specific information about terrestrial plants; the existence of aromatic condensed thiophene compounds is related to the formation of salt lacustrine facies; the ratios of the shortchain alkyl dibenzothiophenic compounds to phenanthrene are the exact indicators of salt lacustrine facies [1]. Onedimensional GC is widely used in the petroleum geological experiments for aromatic fraction analysis. One-dimensional gas chromatography can not satisfy the separation requirements because of its low resolution and low peak capacity. Aromatic fraction contains various kinds of compounds, and compounds with the same aromatic rings have similar volatility, which result in severe peak overlapping in the chromatogram. So identification and quan...
