Molecular Characterization of ■ Aromatics in Gasoline by Gas Chromatography-Mass Spectrometry

作者：Han Xu; Song Chunxia^*; Qian Qin; Li Changxiu; Sun Xinyuan

来源：China Petroleum Processing & Petrochemical Technology, 2023, 25(02): 81-91.

The comprehensive characterization of heavy aromatic hydrocarbons in gasoline is important to optimize the blending process and understand the correlation between aromatics content and engine particulate emissions.However,most current analysis methods can only provide the composition of C8/■ aromatics.In this study,a simple and fast gas chromatography-mass spectrometry (GC-MS) method to identify and quantify ■ aromatics in gasoline was developed.A selected ion monitoring model was employed to eliminate interference from non-aromatic compounds in the detection of target compounds,as well as that between target compounds with different molecular formulas.The identification of C9+aromatics was based on the retention time of model compounds,combined with characteristic mass fragment ions,boiling points,and retention indexes.Seventy-nine C9–C12 aromatic compounds were quantified based on the calibration of representative model compounds,and the method demonstrated good linearity,and high accuracy and precision.Furthermore,the developed methodology was successfully applied to the analysis of gasoline fractions from the reforming,pyrolysis,straight-run,delayed coking,and catalytic cracking processes,as well as commercial gasolines.The results showed that C9 aromatics were the predominant aromatics in all gasoline samples,followed by C10 aromatics.Alkylbenzenes such as C9H12 and C10H14 were the main components in the reforming,straight-run,delayed coking,and catalytic cracking gasoline fractions,as well as in the commercial gasolines,in which 1,2,4-trimethylbenzene and 3-ethyltoluene were dominant;in contrast,aromatics with higher degrees of unsaturation such as indene were the most abundant aromatics in the pyrolysis gasoline fraction.