Modified Method for Determination of PAHs in Ambient Air in Bangkok Using Gas Chromatography-Mass Spectrometry

Abstract

The PAH analysis method was modified using HP-5MS column. Sampling procedure was based on the NIOSH method no.5515. Sorbent tube (XAD-2) and PTFE filter were used to collect PAHs in both gaseous and particulate phases, respectively. The air samples were extracted by n-hexane and analyzed by gas chromatography-mass spectrometry. Results showed that the detection limit of 16 PAHs ranged from 0.6 to 2.4 ng. The percent recoveries of 16 PAHs for sorbent tubes (XAD-2) and PTFE filters were 78.15-90.74% and 78.23-111.55%, respectively.  The percent relative standard deviations were both less than 11%.  The analysis of 20 air samples; 10 samples from the roadside and the other 10 samples from the local market in Bangkok found that total PAH concentrations were 520.56 ± 61.04 and 1248.44 ± 877.93 ng/m³, respectively. The total PAH concentrations from the local market were two times higher than those from the roadside.