Detection and analysis of spin trapped radical adducts using thermal desorption gas chromatography mass spectrometry (TD-GC-MS)

Manzoor, K 2018, Detection and analysis of spin trapped radical adducts using thermal desorption gas chromatography mass spectrometry (TD-GC-MS) , PhD thesis, University of Salford.

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Certain oxygen free radicals are produced constantly in cells by metabolism and exogenous agents. Some, such as the hydroxyl radical, may react with various biomolecules like DNA, lipids or proteins, and thus be involved in the pathogenesis of various diseases. It is often difficult to detect oxygen free radicals due to their relatively short half-life. This problem may be overcome, however, using the spin trapping technique. In this technique, the spin-trap compound is used to trap free radicals, making them stable enough to be analysed using techniques like Electron Paramagnetic Resonance (EPR) spectroscopy or Mass Spectrometry (MS).

In the current study, Fenton chemistry has been used to generate hydroxyl radicals. Since the hydroxyl radical adduct of the spin-trap N-tert-butyl-α-phenylnitrone (PBN) is shortlived at room temperature a secondary trapping technique is employed. The resulting spin-trapped species have been sampled using solvent-free extraction approaches i.e. Headspace Solid Phase Microextraction (HS-SPME) or Thermal desorption (TD), and the extracted products then detected and identified by using gas chromatography-mass spectrometry (GC-MS). GC-MS provides an alternative to other traditional techniques like EPR spectroscopy, as it provides more detailed information about structure of the radical adduct.

Aldehydes are some of the most important products of oxidative stress, mostly produced through lipid peroxidation, and potentially may be used as biomarkers for different diseases. Their reactivity, production in low quantities and need of derivatisation are some of the challenges faced by analytical chemists to detect them. In the current research, aldehydes are used as secondary source of radicals in the Fenton reaction to produce aldehyde related free radicals. The developed method is not only a solvent free approach but also there is no need of derivatisation. It has the potential to be used as a biomarker assay of oxidative stress.

Item Type: Thesis (PhD)
Contributors: Podmore, ID (Supervisor)
Schools: Schools > School of Environment and Life Sciences > Biomedical Research Centre
Depositing User: ID Podmore
Date Deposited: 03 Oct 2018 09:21
Last Modified: 08 Jul 2022 13:21

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