2002 Volume 88 Issue 11 Pages 741-746
This study describes a sampling and analysis procedure for polycyclic aromatic hydrocarbons(PAH) at high temperatures in exhaust gas. Particulate matter sampling was used in conjunction with gas phase sampling. Particulates were collected on quartz fiber filter heated at same temperature as exhaust gas. Vaporous PAH not retained by the filter were cooled at 55°C and trapped from the gas phase on Tenax-GC polymer beads of 10g. The sample volume was about 1m3. Tenax-GC has demonstrated high collection efficiency for benzo(a)pyrene(B(a)P)generated at 375°C under a stream of nitrogen. PAH were extracted with n-pentane for 4h by continuous PAH extractor developed on this study. It demonstrated 99% extraction efficiency for B(a)P spiked on the adsorbent and it was more effective than Soxhlet extraction. The extracts were concentrated to 1ml of n-pentane in a Kuderna-Danish evaporator. Qualitative and quantitative analysis of the extracts were performed by high performance liquid chromatograph (HPLC) with ultraviolet/fluorescence detection. Eight PAH (3, 4, 5, 6-dibenzocarbazole, phenanthrene, anthracene, fluoranthene, pyrene, 2-methylanthracene, benz(a)anthracene, benzo(a)pyrene) were determined in coal combustion gas on reducing NOx procedures. It was demonstrated that the tendency to reduce NOx levels leads to an increase in the PAH present. Moreover total concentration of four PAH (phenanthrene, fluorancene, pyrene, benzo(a)pyrene) in this study is satisfactory agreement with those measured in the emissions of coal-fired power stations in the literature.
