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Application of factor analysis to spectroscopic methods

Application of factor analysis to spectroscopic methods

Brockwell, Timothy Graham (1992) Application of factor analysis to spectroscopic methods. PhD thesis, University of Greenwich.

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Abstract

A computer program has been developed to perform factor analysis and target testing on spectroscopic data. The program offers advantages over other software available on the PC in its ability to work with data matrices of a size limited only by memory and disk space on the computer, and the inclusion of target testing are iterative target testing routines. The program works with numbers of twice the precision of other software and evidence is presented of the improved accuracy of the calculations.

The application of factor analysis to the UV-Vis spectra of a series (quaternary mixtures of transition metal ions is shown. The number of ions in the system is determined and the identities of the ions assigned using target testing. The effect of inadequate sampling intervals of the data is discussed.

Factor analysis is also shown applied to temperature programmed pyrolysis mass spectrometry (TPPy-MS) data where multiple factors are found to arise from single component. The spectra of three substituted ferrocenes are giver 1,4,5,6,7,7-hexachloro-5-norbornene-2,3-dicarboxylic anhydride ferrocene, l-l'(2,4-dichlorobenzoyl) ferrocene, and 3,4-dichlorobenzoyl ferrocene. The source of the multiple components from each of the samples is discussed and used to propose pyrolysis and fragmentation mechanisms. The sensitivity of the factor analysis technique is exemplified by identification of factors due to contaminated source; improper calibration, adsorption effects within the source and bias in the measurement of mass spectra.

The identification of components within mixtures is shown using target testing and the isolation of unknown components demonstrated using both accepted and novel methods of iterative target testing. The properties of the new methods of iterative target testing are investigated. The application of the techniques developed is show using unknown samples analysed by normal analytical techniques. The results of the analysis showed broad agreement with the normal analysis, though the factor analysis indicated the presence of a component not observed in normal analysis and also showed incorrect assignment of another.

Item Type: Thesis (PhD)
Additional Information: uk.bl.ethos.314645 This work has been carried out with the support of the Defence Research Agency, Quality Assurance Technical Support, Royal Arsenal East, Woolwich, London.
Uncontrolled Keywords: atomic physics, molecular physics, atoms, molecules, computer software, chemistry, physical and theoretical atoms, physical chemistry,
Subjects: Q Science > QC Physics
Q Science > QD Chemistry
Pre-2014 Departments: School of Science
School of Science > School of Chemical and Life Sciences
Last Modified: 28 May 2019 14:36
Selected for GREAT 2016: None
Selected for GREAT 2017: None
Selected for GREAT 2018: None
Selected for GREAT 2019: None
URI: http://gala.gre.ac.uk/id/eprint/6117

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