Retention behavior of alkylated polycyclic aromatic sulfur heterocycles on immobilized ionic liquid stationary phases

• We compare retention behavior of 119 PASH on four IL phases and three siloxane phases.
• We examine the effectiveness of IL columns in GC × GC analysis of coal tar.
• Retention is examined in terms of ring number, alkylation, polarity, and polarizability.
• IL columns provide decreased PASH coelution and improved GC × GC separation.

Polycyclic aromatic sulfur heterocycles (PASH) are prevalent components of fossil fuel-based pollutants, and their accurate analysis is of critical importance in risk assessment and hazardous waste site remediation. PASH, however, have a wide range of volatilities and polarities and, as such, often coelute with one another and other sample components on the non-polar gas chromatography (GC) columns commonly used in their analysis. Immobilized ionic liquid (IL)-based stationary phases have been shown to provide better separation of polar compounds than non-polar columns, while withstanding higher temperatures than typical polar columns. In this way, they offer the opportunity of improved performance in the analysis of PASH in complex environmental samples and as the “more polar” column in GC × GC/MS analyses. In this study, the retention behavior of 119 PASH on four commercially-available IL stationary phases is reported and compared to behavior on three polydimethylsiloxane-based columns of varying polarities (DB-5, DB-17, and DB-200). Additionally, the utility of IL columns in GC × GC analyses of PASH-containing coal tar samples is examined.