Abstract
RATIONALE
Coal tars are a mixture of both organic and inorganic compounds and were produced as a by-product from the manufactured gas and coke making industries. The product tar compositions varied depending on many factors such as the temperature of production and the type of retort used. For this reason a comprehensive database of the compounds found within different tar types is of value to both understand how their compositions differ and what potential chemical hazards are present. This study focuses on the heterocyclic and hydroxylated compounds present within a database produced from 16 different tars from 5 different 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 865 Heterocyclic compounds and 359 hydroxylated polycyclic aromatic hydrocarbons were detected within 16 tar samples produced by 5 different production process. Both the heterocyclic and hydroxylated PAH content varied greatly with the production process used with the heterocyclic compounds giving information about the feedstock used. Of the 359 hydroxylated PAHs detected the majority would not be detected without the use of derivatization.
CONCLUSIONS
Coal tars produced using different production processes and feedstocks produced tars with significantly different heterocyclic and hydroxylated contents. The concentrations of the individual heterocyclic compounds varied greatly even within the different production processes and provided information about the feedstock used to produce the tars. The hydroxylated PAH content of the samples provided important forensic information that would otherwise not be obtained without the use of derivatization and GCxGC/TOFMS.
Coal tars are a mixture of both organic and inorganic compounds and were produced as a by-product from the manufactured gas and coke making industries. The product tar compositions varied depending on many factors such as the temperature of production and the type of retort used. For this reason a comprehensive database of the compounds found within different tar types is of value to both understand how their compositions differ and what potential chemical hazards are present. This study focuses on the heterocyclic and hydroxylated compounds present within a database produced from 16 different tars from 5 different 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 865 Heterocyclic compounds and 359 hydroxylated polycyclic aromatic hydrocarbons were detected within 16 tar samples produced by 5 different production process. Both the heterocyclic and hydroxylated PAH content varied greatly with the production process used with the heterocyclic compounds giving information about the feedstock used. Of the 359 hydroxylated PAHs detected the majority would not be detected without the use of derivatization.
CONCLUSIONS
Coal tars produced using different production processes and feedstocks produced tars with significantly different heterocyclic and hydroxylated contents. The concentrations of the individual heterocyclic compounds varied greatly even within the different production processes and provided information about the feedstock used to produce the tars. The hydroxylated PAH content of the samples provided important forensic information that would otherwise not be obtained without the use of derivatization and GCxGC/TOFMS.
| Original language | English |
|---|---|
| Pages (from-to) | 1250-1260 |
| Number of pages | 11 |
| Journal | Rapid Communications in Mass Spectrometry |
| Volume | 31 |
| Issue number | 15 |
| Early online date | 17 May 2017 |
| DOIs | |
| Publication status | Published - 15 Aug 2017 |
Keywords
- GCxGC/TOFMS
- coal tars
- environmental forensics
- derivatization
- chemical hazards
- heterocyclic compounds
- hydroxylated compounds
- accelerated solvent extraction
- two-dimensional gas chromatography
- time-of-flight mass spectrometry