Efficient determination of BTX compounds based on UiO-66-diatomite composite enrichment and thermal desorption GC–MS

Abstract

In this work, a UiO-66-diatomite composite was synthesized and used as sorbent to sample benzene, toluene and xylene (BTX) in indoor air. The physicochemical features of the as-prepared composite were deeply characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), thermo-gravimetric analysis (TGA) and nitrogen adsorption–desorption isotherm analysis. Moreover, an efficient analysis method for the enriched BTX compounds by the UiO-66-diatomite composite was successfully developed using thermal desorption (TD)-GC–MS technique. The influence of desorption temperature was investigated to optimize the operation conditions. Under the desorption temperature of 180 °C, the method depicted good linearity (R2 > 0.99) in the range of 5 ng to 1000 ng as well as excellent reproducibility with relative standard deviation (RSD) between 0.6% and 3.5%, in which the satisfactory recovery was achieved from 75.2% to 115%. More importantly, the developed method also exhibited high sensitivity with the method detection limit (MDL) in the range of 0.04–0.09 μg m−3. Hence, the findings evidence that this method might be one of the promising routes to detect trace levels of BTX compounds in indoor air and the MOF-based composite is feasible to be used as sorbent for the capture of volatile organic compounds in air.