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.

Keywords:

• Gas chromatography – flame ionization detection (GC-FID
• magnetic-silica aerogel
• methyl ethyl ketone (MEK
• molecularly imprinted polymers (MIPs
• neurotoxic chemicals
• n-hexane
• urine

Acknowledgment

This study was supported by the Department of Occupational Health and Safety Engineering, School of Public Health and Safety, Shahid Beheshti University of Medical Sciences (Ethical code: IR.SBMU.PHNS.REC.1399.057).

Conflict of interest statement

The authors have no conflicts of interest to declare relevant to this article’s content.

Funding

This work was supported by the School of Public Health and Safety, Shahid Beheshti University of Medical Sciences, Tehran, Iran.

Data availability

The data generated or analyzed during this study are included in this published article and its supplementary information files.

Additional information

Funding

This work was supported by the School of Public Health and Safety, Shahid Beheshti University of Medical Sciences, Tehran, Iran.