Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.629092
Title: Development of methods of hair analysis using NMR spectroscopy
Author: Briden, Sandra
ISNI:       0000 0004 5348 1581
Awarding Body: University of Reading
Current Institution: University of Reading
Date of Award: 2014
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Abstract:
Forensic analysis of hair remains controversial and new methods of validation are persistently being sought. Although human hair has been the subject of chemical analysis for many years new approaches are always warranted by continual advances in technology. In this thesis a novel rapid and efficient method of hair analysis utilising microwave-assisted acid digestion to break the strong keratin bonds that dominate the hair matrix, coupled with 1 H NMR spectroscopic-based chemometric analysis, is described. Fingerprinting analysis of 265 such hair samples, using 1H NMR spectroscopy, generated peaks in the aliphatic, H. and aromatic regions of the NMR spectra. 1H NMR spectra allowed the determination of a number of metabolites, predominantly human proteinogenic amino acids. The number of peaks acquired in such 'H NMR spectra was large. It was found that the problem of analysing the number of variables present demanded a metabonomic approach in which digests of human hair were treated as a biofluid. Multivariate analysis (MVA) was applied to determine the possibility of identifying discriminatory compounds using principal component analysis (PCA). A comparison with geographical discriminatory factors allowed initial conclusions to be drawn with respect to the identity and relative levels of such metabolites, i.e. threonine. It is proposed that successful application of MVA has the advantage, in forensics, of overcoming bias due to the analyst's personal judgment. Progress in solid-state NMR spectroscopy has been rapid over recent years and hair samples were also subjected to the modern solid-state technique of cross polarization /magic angle spinning (CP-MAS) 13C NMR spectroscopic analysis. Solid-state NMR spectroscopy allows the analysis of samples with minimum sample preparation and with a simple chain of custody. The successful application of both solution-state metabonomics-based NMR and solid-state NMR analysis to hair analysis can be considered as a proof of principle.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.629092  DOI: Not available
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