Ionic Liquid Based Headspace Solid-Phase Microextraction-Gas Chromatography for the Determination of Volatile Polar Organic Compounds

Solid-phase microextraction (SPME) with an ionic liquid (IL) coating was developed for headspace extraction of a group of low molecular weight alcohols (ethanol, n-propanol, butanol, and isopropyl alcohol), acetone, ethyl acetate, and acetonitrile. A first SPME fiber was simply coated with a dedicated IL whose synthesis is described. A second SPME fiber was prepared by gluing silica (Si) particles on which the synthesized IL was chemically bonded. The analytes SPME extraction was optimized for time, temperature, and NaCl salting out content. The headspace extracted analytes were determined by simple temperature desorption into the hot injection port of a gas chromatograph. The coated-IL fiber did not have enough extracting material to be useful. The bonded-IL-Si particle fiber had much more extracting material. Its analytical capabilities were compared to those of two commercially available fibers. The extraction yields of the bonded-IL-Si fiber were inferior to those of the two commercial fibers because they contained a significantly higher amount of extracting material. The linear concentration range could reach up to 120g/mL. The recoveries, trueness, and precision (RSD) were in the 97.4-109.5%, 0.1-9.5%, and 0.7-16.5 ranges, respectively. The bonded-IL-Si fiber showed a specific affinity for ethanol giving an ethanol peak height equal or greater than that of the two commercial fibers tested with the same sample.