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Development of a Novel Mass Spectrometric ... - Jacobs University

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Introduction<br />

Analytical chemistry has been extensively dedicated to the investigation <strong>of</strong><br />

complex mixtures <strong>of</strong> petroleum for the last years. Petroleum and biodegraded or<br />

hydrothermally altered hydrocarbon extracts are known to exhibit unresolved<br />

complex mixtures (UCMs) in gas chromatograms (raised base line termed as<br />

hump) where the exploration <strong>of</strong> the molecular composition <strong>of</strong> these mixtures<br />

becomes limited. 14-17 Among these are the analysis <strong>of</strong> complex mixtures containing<br />

various types <strong>of</strong> hydrocarbons present in waste or oil mixtures and the analysis <strong>of</strong><br />

high-boiling point distillates where adequate chromatographic separation is not yet<br />

available. 10,18,19 Thus the hydrocarbons elsewhere in different mixtures are known<br />

to possess a substantial proportion in which GC is unable to resolve and identify.<br />

Therefore it is emphasized that the existing analytical technology can’t explore the<br />

chemical composition <strong>of</strong> the sample in any other way. For example the large<br />

magnitude <strong>of</strong> the unresolved complex oil components, containing an estimated<br />

250,000 compounds, is not identified, 19 thus a great deal <strong>of</strong> compositional<br />

knowledge remains poorly understood. Such a lack <strong>of</strong> knowledge limits, most<br />

importantly, the assessment <strong>of</strong> effects <strong>of</strong> unresolved complex residues in the<br />

environment. 20<br />

Yet the study <strong>of</strong> complex mixtures has received recent attention since most <strong>of</strong><br />

these mixtures undergo compositional evolution due to some factors like<br />

temperature, time, source, composition, water, and microbial activity. 10,14 It is well<br />

pronounced that a minor change in the composition <strong>of</strong> a mixture can have a huge<br />

effect on its characteristic properties such as flavour, reactivity and toxicity. Such<br />

evolution yields derived products that could be sometimes described as<br />

unrecognized toxins in, for example, marine environment, 8,21 mussel sediment, 22<br />

and crude oil degradation. 23 As well weathering <strong>of</strong> oil spills requires full<br />

understanding <strong>of</strong> the effects and fate <strong>of</strong> spilled products. 24-26 On the other hand,<br />

chemical characterisation and identification <strong>of</strong> heavier components <strong>of</strong> crude oil can<br />

guide refining and production processes necessary in oil industry. Hence the<br />

analysis <strong>of</strong> complex mixture is very important to food chemistry, oil processing as<br />

2

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