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

Certain oxygen free radicals are produced constantly in cells by metabolism andexogenous agents. Some, such as the hydroxyl radical, may react with variousbiomolecules like DNA, lipids or proteins, and thus be involved in the pathogenesis ofvarious diseases. It is often difficult to detect oxygen free radicals due to their relativelyshort half-life. This problem may be overcome, however, using the spin trappingtechnique. In this technique, the spin-trap compound is used to trap free radicals, makingthem stable enough to be analysed using techniques like Electron ParamagneticResonance (EPR) spectroscopy or Mass Spectrometry (MS). In the current study, Fenton chemistry has been used to generate hydroxyl radicals. Sincethe hydroxyl radical adduct of the spin-trap N-tert-butyl-α-phenylnitrone (PBN) is shortlivedat room temperature a secondary trapping technique is employed. The resultingspin-trapped species have been sampled using solvent-free extraction approaches i.e.Headspace Solid Phase Microextraction (HS-SPME) or Thermal desorption (TD), andthe extracted products then detected and identified by using gas chromatography-massspectrometry (GC-MS). GC-MS provides an alternative to other traditional techniqueslike EPR spectroscopy, as it provides more detailed information about structure of theradical adduct. Aldehydes are some of the most important products of oxidative stress, mostly producedthrough lipid peroxidation, and potentially may be used as biomarkers for differentdiseases. Their reactivity, production in low quantities and need of derivatisation aresome of the challenges faced by analytical chemists to detect them. In the currentresearch, aldehydes are used as secondary source of radicals in the Fenton reaction toproduce aldehyde related free radicals. The developed method is not only a solvent freeapproach but also there is no need of derivatisation. It has the potential to be used as abiomarker assay of oxidative stress.

Level dc:type.qualificationlevel

Doctoral (Level 8)

Year dc:date.issued

2018

Author dc:creator

• Manzoor, K

Language dc:language

en

Identifier

oai:salford-repository.worktribe.com:1378296

OAI identifier oai:identifier

oai:salford-repository.worktribe.com:1378296