Thesis
Environmental forensic investigation of derivatisation methods of coal tar using GCxGC TOFMS
- Creator
- Rights statement
- Awarding institution
- University of Strathclyde
- Date of award
- 2013
- Thesis identifier
- T14058
- Person Identifier (Local)
- 201281115
- Qualification Level
- Qualification Name
- Department, School or Faculty
- Abstract
- Coal Tar is a dense non-aqueous phase liquid (DNAPL), which is predominantly found on former manufactured gas plants (FMGP's). These former manufactured gas plants are a large contributor to environmental contamination and more commonly a producer of toxic plumes. These large gas plants produced Gas on a large scale but alongside this primary gas production created many by-products include coal tar. Coal Tar itself is a highly complex mixture of organic and inorganic compounds. Many of these compounds are highly toxic and are known carcinogens. Rough estimations of the number of Former manufactured gas plants in the United Kingdom place the number of sites at over 3000. Many of these sites are a potential environmental disaster source. Coal Tar is a highly complex mixture of organic and inorganic chemicals compounds, which are produced as a result of the carbonization of coal. Many of these compounds are carcinogenic and toxic to humans. Normal end products of coal carbonization include coke or gas. During the carbonization process the production of by products such as Coal Tar is entirely temperature dependant. Coal Tars are commonly a mixture of hydrocarbons, various PAHs, their methyl and polymethyl derivatives, phenols, methylnaphthalenes, picolines, sulphur compounds, nitrogen compounds and heterocyclic Oxygen compounds (IARC 1985). Due to its complex mixture there could possibly be as many as 10,000 compounds present in coal tars many of, which have yet to be identified. Reasons for this include differing production methods between companies, coal source and the distillation process. At the height of the Coal Gas era there were hundreds of companies whose responsibility it was to distill coal tar into different fractions. These different fractions were of higher value to the company and included naphtha, creosote and coal tar pitch. A few of these companies included: Midland Tar Distillers, British Tar Products and Newton Chambers & Company. Coal Tar is often mistakenly identified as being the same as Coal Tar Pitch and Coal Tar Creosote. Coal Tars are most commonly identified visually as a black viscous liquid with a strong pungent smell. The smell is often related to naphthalene or other fuel-like products. Coal Tars are partially soluble in water, acetone and methanol and soluble in benzene and nitrobenzene. Coal Tars are highly flammable and corrosive and when burned it is possible for toxic gases to be produced. As a result their vapours have the potential to form highly explosive mixtures when mixed in air (HSDB 2009). As such there is a great need for the chemical analysis of these coal tar sites because without a comprehensive database of known coal tar source makes analysing and interpreting the results of any other coal tar samples very difficult.;The field of Environmental Forensics primarily deals with the contaminants in an environment, their source, transport pathways and receptors. Legislations such as the EU Environmental Liabilities Directive 2004/35/EC (in the EU) and The Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), December 1980 (in the US) provided powers to governments to pursue polluters and recover the money needed to remediate the site. These legislations bring forward the principal of Polluter Pays to the forefront and have provided drivers for the developments of supporting scientific techniques for contaminant analysis. With each new decade there are great leaps in technological abilities and year on year the instrumentation also improves alongside this. These improvements provide a scientifically robust and reliable analysis, which supports the polluter-pays principle. An example of an analytical technique, which has improved alongside technological advances is Two-dimensional chromatography (GC x GC) coupled with Time of Flight Mass Spectroscopy (TOFMS). The GC x GC instrumentation allows for a much greater separation of complex compound mixtures and the Time of Flight Mass Spectrometer allows for their identification to a high level of accuracy. In this dissertation the main body of work analysed a specific coal tar sample in order to determine whether different solvent mixtures had any effect on the derivitisation of the coal tar. Also studied was the effectiveness of in cell clean up using Silica in comparison with after cell clean up. In this work a single step analytical method previously developed provided a standard method for the analysis of coal tars and also the preparation of samples. Using automated sample extraction in conjunction with the GC x GC TOFMS yielded accurate results, which could clearly be identified but in much less time than normal analysis. The ability of the GC x GC to provide a much higher separation compared to a normal GC allows for a greater in depth study of the chemical data, which is very difficult to study but provided greater data on previously unidentified compounds.
- Resource Type
- DOI
- Date Created
- 2013
- Former identifier
- 1231464
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