A comparison between the vacuum ultraviolet photoionization time-of-flight mass spectra and the GC/MS total ion chromatograms of polycyclic aromatic hydrocarbons contained in coal soot and multi-component PAH particles

Abstract

This paper reports a comparison between the vacuum ultraviolet photoionization time-of-flight mass spectra and the gas chromatography–mass spectrometry total ion chromatograms of polycyclic aromatic hydrocarbons (PAHs) contained in soot particles and multi-component PAH particles. The soot particles are produced by burning a small amount of screened bituminous coal powder in a tubular oven under synthesized air. The soot particles generated are analyzed on-line with a vacuum ultraviolet photoionization aerosol time-of-flight mass spectrometer (VUV-AMS) and off-line with a gas chromatography–mass spectrometer (GC/MS). 55 PAHs are observed with the GC/MS, while parent ions of 54 PAHs are observed with the VUV-AMS. The multi-component PAH particles are generated by atomizing 16 PAHs in isopropyl alcohol. The PAHs are defined as 16 primary pollutants by the Environmental Protection Agency of the United States. GC/MS identifies the 16 PAHs while VUV-AMS observes 15 PAHs with missing the mass peak of naphthalene. The relationship of the PAH sensitivity of VUV-AMS and GC/MS vs. the molecular weights of the PAHs are obtained.