Use of switchable hydrophilicity solvents based liquid phase microextraction (SPs-LPME) followed by GC-FID for the determination of 42 petroleum pollutants in water samples

In recent years, there has been considerable interest in the determination of contaminants of petroleum hydrocarbons in residential indoor air, soil and water samples. Considerable amounts of petroleum compounds are discharged into the environment through industrial effluents [1-3]. In the present study, switchable hydrophilicity solvents based liquid phase microextraction (SPs-LPME) [4-5] followed by GC-FID was applied for the simultaneous determination of the trace concentrations of 42 petroleum pollutants in water. The optimization of the variables affecting this method was carried out. Dipropylamine was used as extraction solvent with switchable hydrophilicity that can be miscible or immiscible upon the addition or removal of CO2 as a reagent. The major benefits of this technique is mainly the very large surface area between the fine droplets of the extraction solvent and the aqueous sample, and the accordingly fast extraction kinetics that result in the rapid achieving of a state of equilibrium and the high enrichment factors (376–500) usually obtained. Under the optimum conditions, proposed method provided low limits of detection (0.15–0.99 µg L−1) and acceptable extraction repeatabilities (RSD%= 3.7-5.4). It was linear over two orders of magnitude. Finally, the developed methods were successfully used in determination of the concentrations of petroleum pollutants in different types of natural water samples and acceptable recoveries ( 82%) were obtained.