Combined Comprehensive Two-Dimensional Gas Chromatography Analysis of Polyaromatic Hydrocarbons/Polyaromatic SulfurContaining Hydrocarbons (PAH/PASH) in Complex Matrices

A new gas chromatographic method has been developed that is able to quantify polycyclic aromatic hydrocarbons (PAH) and polycyclic aromatic sulfur-containing hydrocarbons (PASH) up to four rings. The method combines the power of both flame ionization detection (FID) and sulfur chemiluminescence detection (SCD) in series on a single comprehensive two-dimensional gas chromatography (GC x GC) system and provides mass fractions of compounds separated by carbon number n (CnHxSy) and class. In addition to PAH and PASH separation, the method is extended toward nonaromatic and monoaromatic (sulfur-containing) compounds (paraffins, naphthenes, monoaromatics, thiols, sulfides, disulfides, and thiophenes). The 95% confidence interval is doubled when a single injection technique is used instead of a more-accurate double injection technique. A flexible correction procedure that combines the advantages of the two-dimensional separation of GC x GC and its ability to easily define overlapping groups between the FID and the SCD chromatograms is applied. The method is validated using theoretical reference mixtures and is applied on three commercial gas oils with sulfur content from 0.16 wt% up to 1.34 wt%. The repeatability is good, with an average of 3.4%, which is in the same range as the much more expensive Fourier transform ion cyclotron resonancemass spectroscopy (FTICR-MS) technique.