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Detailed structural characterisation of agrochemicals via advanced mass spectrometry techniques
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Marzullo, Bryan Pietro (2022) Detailed structural characterisation of agrochemicals via advanced mass spectrometry techniques. PhD thesis, University of Warwick.
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Official URL: http://webcat.warwick.ac.uk/record=b3851569
Abstract
This thesis focuses on the applicability of two-dimensional mass spectrometry (2DMS) as a viable and presentable technique for the data-independent structural characterisation of singly charged agrochemicals and their metabolites in model environment matrices.
Firstly, tandem MS experiments were performed to assess the structurally informative data achievable by an electron-based dissociation technique, EID, that can be applied to singly charged agrochemical ions. EID allowed more comprehensive characterisation of these interesting species, especially with respect to the increased cross-ring cleavages compared to the more common CAD MS/MS (chapter 2).
The work presented throughout chapters 3 to 5 of this thesis showcase a number of features and advancements in the use of 2DMS for the structural characterisation of these complex samples. Two radially-defined fragmentation techniques (IRMPD and EID) were used to obtain structural informative data of an agrochemical mixture by 2DMS, demonstrating the advantages of this data-independent analysis (DIA) technique, while comparing 2DMS data to tandem MS data (chapter 3). 2DMS coupled with UVPD fragmentation results in abundant structural characterisation of compounds within an agrochemical complex sample, leading to an increased moiety characterisation compared to the tandem MS results. UVPD provided enhanced cross-ring cleavages, similar to EID, whilst utilising a dissociation technique that is less complex to tune. A novel 2DMS data extraction method, 3D peak picking, is demonstrated to discriminate between closely m/z spaced precursors with a peak centre standard deviation of ~ 3.8 mDa, whilst reducing the complexity of the extracted spectra (chapter 4).
The application of 2D-UVPD-MS is further demonstrated on a sample containing an agrochemical and its metabolites within environmentally relevant matrices, showing the facile structural characterisation of the species of interest within a complex mixture (~ 2850 peaks detected) with drastically varying peak intensities (4 - 5 orders of magnitude) and without the use of chromatographic separation (chapter 5). This displays the potential of 2DMS as a powerful analytical tool for the analysis of complex samples, specifically aiding in metabolite identification through the use of precursor scans, neutral loss, and fragment data.
Item Type: | Thesis (PhD) | ||||
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Subjects: | Q Science > QD Chemistry T Technology > TD Environmental technology. Sanitary engineering |
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Library of Congress Subject Headings (LCSH): | Mass spectrometry, Agricultural chemicals, Dissociation, Photodissociation | ||||
Official Date: | February 2022 | ||||
Dates: |
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Institution: | University of Warwick | ||||
Theses Department: | Department of Chemistry | ||||
Thesis Type: | PhD | ||||
Publication Status: | Unpublished | ||||
Supervisor(s)/Advisor: | O'Connor, Peter B. | ||||
Format of File: | |||||
Extent: | xxxiii, 380 leaves : illustrations, charts | ||||
Language: | eng |
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