Determination of 70 liquid crystal monomers in indoor gas-particle-dust multi-medium based on ultrasonic extraction coupled with comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry

Liquid crystal monomers (LCMs) are a class of emerging organic pollutants widely used in liquid crystal displays (LCDs) of various electronic products. LCMs can easily be released from LCDs into indoor environments and may pose potential environmental and health risks. Meanwhile, LCMs exhibit a wide range of saturation vapor pressures (PL) and octanol-air partition coefficients (Koa), which enable their presence in various indoor metrices. However, current research on LCMs within indoor multi-medium contexts remains limited. The development of effective analytical methods could significantly advance related research endeavors. This study developed a method using ultrasonic extraction to extract 70 LCMs from dust, gas, and particle samples, and analyzed them using comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC × GC-TOF MS). The recoveries of 70 LCMs in dust, gas and particle phases ranged from 77.7 % to 116 %, 73.8 %–127 %, and 62.1 %–147 %, respectively. The instrument's detection limits and quantification limits were 0.01–1.10 ng/mL and 0.04–3.67 ng/mL, respectively. This demonstrated that the method exhibited satisfactory accuracy and sensitivity, and was further applied to analyze 70 LCMs in indoor dust, gas, and particle phases. 52 LCMs were detected in all three matrices, with significant differences in the distribution of these LCMs across the multi-medium. This method is suitable for determining LCMs concentrations in dust, gas, and particle phases, facilitating a more comprehensive analysis of the occurrence levels of indoor LCMs, and providing a technical reference for future studies on the partitioning behavior and risk assessment of LCMs in indoor multi-medium environments, thereby enhancing our understanding of their environmental impact.