Bio-monitoring of non-metabolized BTEX compounds in urine by dynamic headspace-needle trap device packed with 3D Ni/Co-BTC bimetallic metal-organic framework as an efficient absorbent

Abstract

In this work we try to develop a new analytical procedure for extraction and analysis of the Benzene, Toluene, Ethylbenzene and Xylene isomer compounds in the urine samples. In this way, we employed the 3D Ni/Co-BTC bimetallic metal–organic framework as new and efficient solid absorbent packed inside a Dynamic Headspace Needle Trap Device for extraction of the Benzene, Toluene, Ethylbenzene and Xylene isomer compounds. For more details, full characterization of the synthesized adsorbent performed by X-ray diffraction, Field emission scanning electron microscopes, Fourier-transform infrared spectroscopy and elemental mapping techniques. In the bench scale, the extraction and thermal desorption parameters such as temperature, time, and percentage salt optimized by Response Surface Methodology and Box Behnken Design. The obtained results exhibited that the optimal extraction time, extraction temperature and salt content of the sample were 35 min, 35°C and 7.5%, respectively. Also, the optimal temperature and time of thermal desorption were determined to be 275°C and 3 min, respectively. The method detection limit of mentioned compounds by this method were in the range of 0.2–1.1 ng.mL−1 that proves the high sensitivity of the proposed method. Moreover, the percentage relative recovery of desired analytes was obtained in the range of 95–99%. The repeatability and reproducibility of proposed method were obtained in the range 1.9–5.8% and 5.5–8.2% respectively, which indicates the acceptable precision of the method. Eventually, this method was successfully employed to determination of Benzene, Toluene, Ethylbenzene and Xylene isomer compounds in the real urine samples. Findings indicated that proposed method can be used to fast, simple and sensitive biological monitoring of non-metabolized Benzene, Toluene, Ethylbenzene and Xylene compounds in the urine samples.