Characterization of phenolic compounds in coal tar by gas chromatography/negative-ion atmospheric pressure chemical ionization mass spectrometry.

Abstract

Phenolic compounds are commonly found in fossel fuels and bio-oils, and have a detrimental effect on the chemical stability of the fuels. A selective analytical method is needed to characterize the phenolic compounds in complex hydrocarbon mixtures. Gas chromatography/atmospheric pressure chemical ionization mass spectrometry (GC/APCI-MS) was used to characterize the phenolic compounds in a low-temperature coal tar and its narrow distillate fractions. Negative-ion APCI selectively ionized phenolic compounds in the coal tar. The [M-H](-) and [M-H+O](-) ions were derived from monohydric phenols, while [M-H](-) , [M-2H](-) , and [M-2H+O](-) were from benzenediols. Monohydric phenolic compounds with 1-4 aromatic rings and some dihydric phenolic compounds were identified. The results from GC/APCI-MS were validated by those from negative electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FTICRMS). Negative-ion GC/APCI-MS was proposed and successfully used to characterize phenolic compounds in coal tar samples. This technique can potentially be used for the characterization of phenolic compounds in other complex hydrocarbon systems. Copyright © 2016 John Wiley & Sons, Ltd.