Filtration efficiency validation of glass wool during thermal desorption–gas chromatography–mass spectrometer analysis of fine atmospheric particles

Abstract

Thermal desorption–gas chromatography–mass spectrometer (TD–GC–MS) technique has been widely used for analysis of semi-violate organic compounds on atmospheric aerosol. To prevent GC column from being damaged by fine solid particles during thermal desorption process, glass wool as filter mat is indispensible. However, the filtration efficiency has never been validated. In this paper, the most penetrating particle size and the minimum packing thickness of glass wool were calculated based on classical filtration theory. According to the calculation results, packing parameters of glass wool were optimized experimentally using silica particles. It is demonstrated that glass wool with a packing thickness of 30mm, solidity of 0.039 can effectively block these fine solid particles from penetrating at normal thermal desorption conditions (T=300°C, u=0.4–4cm/s). Finally, the filtration efficiency of glass wool was further confirmed with real PM2.5 samples. Under the validated filtration condition, TD–GC–MS was applied for the analysis of non-polar organic compounds on real PM2.5 samples, and very good results were obtained.