Examination of analyte partitioning to monocationic and dicationic imidazolium-based ionic liquid aggregates using solid-phase microextraction-gas chromatography

Solid phase microextraction coupled to gas chromatography has been used to study the partitioning behaviour of several analytes to four monocationic and two dicationic imidazolium-based ionic liquid (IL) aggregates. The 14 different analytes studied consisted of aliphatic hydrocarbons, polycyclic aromatic hydrocarbons, phenols, and esters. The obtained partition coefficients for analytes that exhibited partitioning into the IL-aggregates ranged from 30 to 5200. Hydrophobic analytes (with octanol-water partition coefficients higher than 300) appear to be preferably extracted over more polar analytes revealing the possibility of carrying out selective extractions using these aggregate systems. Monocationic IL-aggregates generally exhibited higher partition coefficients compared to analogous dicationic ILs. The micellar shape of the IL-aggregates also influences the extent of analyte partitioning.