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

Manzoor, K

Abstract

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.

Citation

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

• Thesis Type: Thesis
• Acceptance Date: Sep 28, 2018
• Deposit Date: Oct 3, 2018
• Publicly Available Date: Sep 29, 2023
• Award Date: Sep 28, 2018