Determination of eight volatile benzene series in e-cigarette liquids and aerosols by thin-film solid-phase microextraction/GC-QTOF-MS

Monitoring harmful volatile organic compounds in e-cigarettes is crucial for product quality assessment and consumer safety. In this study, a polydimethylsiloxane (PDMS) film embedded with 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine (H₃TATB)-modified MIL-101(Cr) particles was prepared via dip-coating to serve as a solid-phase microextraction (SPME) medium. Gas chromatography-quadrupole time-of-flight mass spectrometry (GC-QTOF-MS) method was developed and optimized using this custom SPME film for the determination of eight volatile benzene-series compounds in commercial e-cigarette products. The analytical method was applied to 43 electronic cigarette (e-cigarette) samples, enabling the quantification of target compounds in both e-liquids and aerosols. The method exhibited excellent linearity and high mass accuracy, with limits of quantifications (LOQs) ranging from 0.0016 to 0.0090 µg·g⁻¹ and 0.0037 to 0.0208 µg·20 puffs⁻¹ in e-liquids and aerosols, respectively. Limits of detections (LODs) ranged from 0.0054 to 0.0298 µg·g⁻¹ and 0.0122 to 0.0686 µg·20 puffs⁻¹ for e-liquids and aerosols, respectively. Recoveries of the target compounds in e-liquids ranged from 70.12% to 107.06%. Among the eight compounds, benzene, toluene, and ethylbenzene were consistently detected in both sample types. Benzene concentrations ranged from 0.837 to 5.107 µg·g⁻¹ in e-liquids and 0.201 to 4.179 µg·20 puffs⁻¹ in aerosols; ethylbenzene was present at 0 to 0.798 µg·g⁻¹ and 0 to 1.608 µg·20 puffs⁻¹, respectively. The study presents a rapid, sensitive, and reliable method for analysing volatile benzene-series compounds in complex e-cigarette matrices. The developed approach supports regulatory oversight and contributes to establishing effective quality control systems for e-cigarette products.