Determination of BTEX in air samples using a needle trap device packed with a Zeolite@MOF composite adsorbent

In this study, for the first time, a zeolite/metal-organic framework composite (H-ZSM-5/UiO-66) was employed as a novel adsorbent in a needle trap device (NTD) for the sampling and analysis of BTEX compounds in air. The structure and morphology of the synthesized composite were characterized using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), and thermogravimetric analysis (TGA). The key parameters affecting sampling performance, including sampling temperature and relative humidity, as well as thermal desorption conditions (desorption temperature and time), were optimized using response surface methodology (RSM). The optimal sampling conditions were determined to be 20 °C and 20% relative humidity, while the practical desorption conditions were set at 275 °C for 5 min to ensure efficient desorption of all BTEX compounds. The limits of detection (LOD) and limits of quantification (LOQ) for the target analytes were found to be in the ranges of 0.11-0.40 mg m^-3 and 0.41-1.20 mg m^-3, respectively. The developed method exhibited a wide linear dynamic range (LDR) up to 800 mg m^-3, with inter-day and intra-day relative standard deviations (RSD) ranging from 6.9% to 8.2% and 3.1% to 7.9%, respectively. Inter-device reproducibility, evaluated using three independent NTDs, demonstrated acceptable precision with RSD values ranging from 7.8 to 10.3%. The analytical performance of the proposed method was further validated by comparison with the NIOSH 1501 reference method, showing good agreement between the two approaches. Finally, the H-ZSM-5/UiO-66-packed NTD was successfully applied to the determination of BTEX in real air samples, confirming its suitability as a simple, solvent-free, and practical approach for environmental and occupational air monitoring.