Development of a multi-channel diffusive sampling system for the analysis of Semi-Volatile Organic Compounds in the...

The tendency of SVOCs to partition between the vapor and particulate phases influences the reaction kinetics of these pollutants, pushing for the development of selective sampling systems. Traditional methods like filters and adsorbents have limited accuracy in describing the distribution of SVOCs due to sampling artifacts, such as analyte stripping during active air sampling. This distinction is crucial for designing pollutant abatement systems in industrial settings and developing collective and individual protection devices against airborne chemical agents.

This study presents the development of a multi-channel diffusion denuder for the sampling and the selective enrichment of SVOCs in the vapor phase for subsequent direct determination through thermal desorption coupled with GC/MS. The analysis of compounds sampled using the denuder was compared with that of a common granular carbon trap. The multi-channel denuder has been evaluated for its ability to selectively sample the vapor phase of an aerosol without retaining the particulate phase. It was demonstrated that, on average, this type of denuder retains only 13% of the total particulate matter, with Aed between 14 and 800 nm. Total transmission is achieved for particles with Aed greater than 800 nm. An ozone scrubber prevents degradation and oxidation product formation, showing effective preservation of compounds in the presence of ozone.

Results show that denuder sampling significantly improves chromatographic resolution and efficiency. The multi-channel denuder developed in this study proved to be an efficient tool for selectively sampling SVOCs in the vapor phase, making it particularly suitable for indoor air monitoring and workplace exposure assessment. Theoretical calculations showed efficiencies higher than 95% for all analytes.