Development of metal oxide-based solid phase Microextraction fiber for the determination of volatile organic compounds

Abstract

Volatile organic compounds (VOCs) have high vapor pressures and readily evaporate at room temperature, thereby accumulating in the indoor environment, so their levels frequently exceed outdoor levels. Due to the harmful effects of many VOCs, such as benzene, toluene, ethylbenzene and xylenes (BTEX) on human health, effective monitoring of these compounds in the indoor environment is quite important. The conventional techniques are often poor sensitivity, costly and necessitate the expertise of specialists or the procurement of sophisticated equipment. Therefore, the development of rapid, sensitive, cost-effective, and straightforward analytical methods for the monitoring of them in indoor environments is required. In this study, a fast, easy, cost-effective, and sensitive gas chromatographic method based on the metal oxide solid phase microextraction (SPME) fiber was developed for the monitoring of BTEX in the indoor environment. The performance of different metal oxide coatings, such as TiO₂, RuO₂, and IrO₂, was tested. The best BTEX extraction efficiencies were obtained by IrO₂-SPME-Fiber. To get the best extraction efficiency, IrO₂-SPME-Fiber coating conditions, including Ir, IPA, and HCl concentrations, calcination temperature and coating cycle number, were optimized by Taguchi experimental design. Then, the sampling conditions, including extraction time, extraction temperature and sample volume, were optimized to get better extraction efficiency. Under optimized conditions, the method exhibited linearity over the range of 0.04–700 ppmv, with R² = 0.998–0.9995. The limits of detection for BTEX compounds were 0.015–0.142 ppmv, with acceptable repeatability (RSD < 10%). The method was successfully applied for the analysis of BTEX in indoor air samples with an acceptable recovery (85–107%).