Selective Determination of n-Hexane and Methyl Ethyl Ketone (MEK) in Urine by Magnetic-Silica Aerogel-Based Molecularly Imprinted Polymers (MIPs) with Gas Chromatography – Flame Ionization Detection (GC-FID)

Abstract

Co-exposure to n-hexane and methyl ethyl ketone (MEK) may induce neurotoxicity in humans. Since biomonitoring of exposed chemicals is a powerful hygienic way of controlling chemical risk, a new molecularly imprinted polymer (MIP) is reported in this study. Polymerization was carried out upon the surface of magnetic silica aerogel (Si@Fe3O4) using 2-octanone as a dummy template to prepare Si@Fe3O4-MIP. The synthesized MIP was characterized by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectrometry thermogravimetric analysis (TGA), Brunauer–Emmett–Teller (BET) analysis, and vibration sample magnetometry (VSM). The reported method was utilized for the selective extraction of n-hexane and MEK from humane urine using gas chromatography – flame ionization detection (GC-FID). The highest selectivity coefficient of Si@Fe3O4-MIP was obtained for n-hexane and MEK. The validity of solid phase extraction (SPE)-based Si@Fe3O4-MIP was confirmed by the recovery (> 93.6%) and acceptable reproducibility was obtained with relative standard deviations between 1.6 and 8%. The limit of quantifications (LOQ) for n-hexane and MEK were 1.5 and 128 µg/L, respectively. The validated SPE-based Si@Fe3O4-MIP is suggested for determining n-hexane and MEK in urine of shoemaker workers for biomonitoring purposes.