2017 Volume 27 Issue 4 Pages 145-152
A new, comprehensive method for measuring selected aromatic VOCs in low concentrations in air was developed. The method is composed of selective sampling for benzene, toluene, xylene and ethyl benzene (Aromatic VOCs) by using a combination of two different adsorbent tubes, followed by thermal desorption and detection of whole components by a FID device. The adsorbents were selected by testing adsorption abilities for the target compounds, using an experiment system with model gases; the combination of Tenax TA and Carbotrap B adsorbents was found to be most suitable. The measurement method provided 0.1 μg/m3 of detection limit that corresponded to 0.19 ppbC and 0.3 μg/m3 of quantitation limit that corresponded to 0.58 ppbC as toluene equivalent concentration, which enabled the measurements in and around recycling plants of waste plastics. The maximum air sampling amount of 200 L was confirmed without breakthrough phenomena. In case of coexisting volatile aliphatic compounds such as acetone, which could be firstly removed by Carboxen 1000 adsorbent that has high adsorption ability for a wide range of compounds, and the target aromatic VOCs can be selectively determined.
