Ionogel sorbent coatings for determining organophosphorus and pyrethroid insecticides in water and fresh juice samples by headspace-solid phase microextraction

Abstract

The sol–gel method yielded three different ionogel sorbent coatings that were obtained based on a silica material containing ionic liquids (ILs) immobilized in its pores. Two ILs, triethylsulfonium bis(trifluoromethylsulfonyl)imide [Set3][TFSI] and 1-butyl-1-methylpiperidinium bis(trifluoromethylsulfonyl)imide [C4C1Pip][TFSI], as well as their equimolar mixture [Set3/C4C1Pip], were used to obtain ionogel fibers. The developed sorbents were applied to extract six different insecticides from liquid samples. The crucial extraction parameters of headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography with flame ionization detection (GC-FID) method were optimized with a central composite design. The ionogel fibers demonstrated higher selectivity for extracting the analyzed insecticides compared with commercially available fibers. The calculated values of the enrichment factor were in the ranges of 41,400–106,100 for [Set3], 110,600–170,500 for [C4C1Pip], and 76,800–121,100 for [Set3/C4C1Pip]. The [Set3/C4C1Pip] ionogel fiber, demonstrated the highest selectivity for extraction the insecticides. Regarding this coating, the limit of detection in the range of 0.02–0.95 μg L−1, coefficient of determination, which were <0.9690, and a 2.1 %–6.5 % repeatability of the method were achieved. Finally, the obtained ionogel fibers were utilized to determine insecticides in fresh apple and carrot juices.