In the search for the conformation of extant or extinct life in an
extraterrestrial setting the detection of organic molecular species
which may be considered diagnostic of life is a key objective. These
molecular targets comprise a range of distinct chemical species,
with recognisable spectroscopic features. This project aims to use
these features to develop an in-situ molecular specific Raman spectroscopic
methodology which can provide structural information about
the organic–inorganic interface.
The development of this methodology identified a surface enhanced
Raman spectroscopic technique, that required minimal sample preparation,
allowed for the detection of selected organic species immobilised
on an inorganic matrix and was effective for quantities below
those which conventional dispersive Raman spectroscopy would detect.
For the first time spectral information was gained which allowed
analysis of the organic–inorganic interface to be carried out, this
gave an insight into the orientation with which molecules arrange on
the surfaces of the matrices. Additionally a method for the detection
of organic residues intercalated into the interlamellar space of smectite
type clays was developed. An evaluation of the effectiveness of
uni and multivariate methods for the analysis of large datasets containing
a small number of organic features was also carried out, with a view to develop an unsupervised methodology capable of performing
with minimal user interaction. It has been shown that a novel
use of the Hotellings T2 test when applied to the principal component
analysis of the datasets combined with SERS allows identification
of a small number of organic features in an otherwise inorganic
dominated dataset.
Both the SERS and PCA methods hold relevance for the detection
of organic residues within interplanetary exploration but may also be
applied to terrestrial environmental chemistry.
| Identifer | oai:union.ndltd.org:BRADFORD/oai:bradscholars.brad.ac.uk:10454/7332 |
| Date | January 2013 |
| Creators | Whitaker, Darren A. |
| Contributors | Scowen, Ian J., Munshi, Tasnim |
| Publisher | University of Bradford, Chemical and Forensic Sciences |
| Source Sets | Bradford Scholars |
| Language | English |
| Detected Language | English |
| Type | Thesis, doctoral, PhD |
| Rights | <a rel="license" href="http://creativecommons.org/licenses/by-nc-nd/3.0/"><img alt="Creative Commons License" style="border-width:0" src="http://i.creativecommons.org/l/by-nc-nd/3.0/88x31.png" /></a><br />The University of Bradford theses are licenced under a <a rel="license" href="http://creativecommons.org/licenses/by-nc-nd/3.0/">Creative Commons Licence</a>. |
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