Date of Award

January 2023

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Chemistry

First Advisor

Evguenii E. Kozliak

Abstract

High-Performance Liquid Chromatography-Mass Spectrometry (HPLC-MS) is a versatile technique that has vast applications in analytical chemistry, specifically for the identification, quantitation, and mass analysis of components. This study outlines an exploration of HPLC-MS applications, focusing on its utilization in two distinct areas: lignin degradation studies and forensic investigations.Lignin degradation: Most of the previous studies on lignin degradation, employed gas chromatography-mass spectrometry (GC-MS) for product characterization. Most lignin model compounds, which are widely used in lignin valorization studies, are either not GC-elutable or have low thermal stability. In this work we investigated HPLC-MS as an alternative method, which offers a simultaneous quantification of both model compounds and their breakdown products. We assessed the applicability of guaiacylglycerol-β-guaiacylether (Gβ2) as a model compound for evaluating the efficiency of β-O-4 bond cleavage under different experimental conditions including varied pH, biodegradation, subcritical water environment, and mild pyrolysis. Forensic investigations: Some drug determination is crucial in the court of law in cases of homicide and suspect death. In cases when human tissues are either severely decomposed or inadequate for sampling, necrophagous insect species are used to investigate the presence of putative drugs by determining their bioaccumulation in insect tissues. HPLC-MS as a sensitive and selective method can be utilized for forensic investigations that deal with low levels of benzodiazepines, to further understand the effect of these drugs on the development cycle of primary insect colonizers, thus on the estimation of the post-mortem interval (PMI). The determination of benzodiazepine and their metabolites concentration of two different groups of samples including “benzodiazepine-spiked samples” and “exposed samples with benzodiazepine-contaminated liver”, is achieved through HPLC-MS, based on the internal standard calibration. The correction of these concentrations is performed using a recovery standard with an evaluation of three different extraction methods and their impact on sample concentration determination via HPLC-MS, along with an analysis of the contaminated liver itself.

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