Comprehensive database of Manufactured Gas Plant tars – Part A Database

Gallacher, Christopher and Thomas, Russell and Lord, Richard and Kalin, Robert M. and Taylor, Chris (2017) Comprehensive database of Manufactured Gas Plant tars – Part A Database. Rapid Communications in Mass Spectrometry, 31 (15). pp. 1231-1238. ISSN 0951-4198 (

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Rationale Coal tars are a mixture of organic and inorganic compounds and were by-products from the manufactured gas and coke making industries. Different manufacturing processes have resulted in the production of distinctly different tar compositions. This study presents a comprehensive database of compounds produced using two-dimensional gas chromatography combined with time-of-flight mass spectrometry (GCxGC/TOFMS), analysing 16 tar samples produced by 5 distinct production processes. Methods Samples of coal tar were extracted using accelerated solvent extraction (ASE) and derivatized post extraction using N,O-Bis(trimethylsilyl)trifluoroacetamide (BSTFA) with 1% trimethylchlorosilane (TMCS). The derivatized samples were analysed using two-dimensional gas chromatography combined with time-of-flight mass spectrometry (GCxGC/TOFMS). Results A total of 16 tar samples originating from 5 different production processes: Low Temperature Horizontal Retorts, Horizontal Retorts, Vertical Retorts, Carbureted Water Gas and Coke Ovens, were analysed. 2369 unique compounds were detected with 948 aromatic compounds, 196 aliphatic compounds, 380 sulphur-containing compounds, 209 oxygen-containing compounds, 262 nitrogen-containing compounds and 15 mixed heterocycles. Derivatization allowed the detection of 359 unique compounds, the majority in the form of hydroxylated polycyclic aromatic hydrocarbons, many of which would not have been detected without derivatization. Of the 2369 unique compounds detected 173 compounds were found to be present within all samples. Conclusions A unique comprehensive database of compounds detected within 16 tar samples from 5 different production processes was produced. The 173 compounds identified within every sample may be of particular importance from a regulatory standpoint. This initial study indicates that different production processes produce tars with different chemical signatures and it can be further expanded upon by in-depth analysis of the different compound types. The number of compounds presented within this database clearly demonstrates the analytical power of GCxGC/TOFMS.


Gallacher, Christopher ORCID logoORCID:, Thomas, Russell, Lord, Richard ORCID logoORCID:, Kalin, Robert M. and Taylor, Chris;