Dendrimer grafted nanoporous silica fibers for headspace solid phase microextraction coupled to gas chromatography determination of solvent residues in edible oil

Abstract

A recently prepared nanoporous G(1)-dendrimer supported Santa Barbara Amorphous-15 (SBA-15) solid phase microextraction (SPME) fiber was successfully applied to the headspace solid-phase microextraction of solvent residues such as hexane, benzene, and toluene in edible vegetable oils followed by gas chromatography flame ionization detection (GC-FID). Experimental conditions such as extraction time and temperature and GC parameters were optimized. Under the optimized conditions, linear calibration curves were obtained in the ranges of 6–300 mg kg⁻¹ for hexane, and 8–250 mg kg⁻¹ for both benzene and toluene. The detection limit was the concentration of the analyte having a signal three times that of the noise and was in the range of 0.90–1.2 mg kg⁻¹ for the three mentioned solvents. The relative standard deviations (RSDs) for hexane, benzene, and toluene under optimum conditions were 9.50, 6.70, and 7.30% for a fiber (repeatability, n = 6) and 12.1, 9.30, and 14.90% between fibers (reproducibility, n = 6), respectively. The method was successfully applied to the extraction and determination of the three solvents in ten different vegetable oils collected from local markets. The results were in good agreement with those obtained using the commercial fibers.