Detection, differentiation, and quantification of BTX compounds using high-field asymmetric waveform ion mobility spectrometry.

Benzene, toluene, and xylene, also known as BTX compounds, are toxic volatile organic compounds (VOCs) that are widely distributed in the environment and affect human health. An effective BTX compound monitoring method is urgently needed for environmental pollution control. This work demonstrates the ability of high-field asymmetric waveform ion mobility spectrometry (FAIMS) to detect, differentiate, and quantify BTX compounds. The FAIMS full spectra of benzene, toluene, and xylene were constructed by self-developed FAIMS. At an optimal dispersion voltage of 800 V, the separation of the mixture was optimized by improving the gas conditions. The BTX compounds were quantified in the concentration range of 50-250 ppb. According to the experimental results, FAIMS has achieved detection of benzene, toluene, and xylene, with a limit of detection (LOD) range of 5.64-16.37 ppb. The BTX monomers were successfully differentiated in the dispersion voltage range of 550-1000 V, and the addition of isopropanol and water vapor enhanced the separation of their mixture. In the optimal case, the coefficient of determination for xylene in the linear range of 18.81-250 ppb exceeded 0.999, which realized the quantification of BTX compounds by FAIMS. This study provides an effective method for monitoring BTX compounds.