The detection and characterisation of novel alkyl spin-adducts of PBN and its derivatives using capillary gas chromatography coupled to electron-ionisation mass spectrometry
Free radical induced oxidative stress has been reported to be involved in several diseases such as diabetes mellitus, neurodegenerative disorders, cardiovascular diseases (atherosclerosis and hypertension), respiratory diseases (asthma), cataract development, rheumatoid arthritis and in various cancers (colorectal, prostate, breast, lung, bladder cancers). Aldehydes are strong electrophilic compounds with terminal carbonyl groups making them highly reactive. Aldehydes may react with hydroxyl radicals forming radicals which, in turn, react with cellular components. Hydroxyl free radicals were generated by Fenton-based chemistry and reacted with aliphatic aldehydes to produce secondary radicals in the presence of the spin-trapping agent N-tert-butyl-a-phenylnitrone (PBN). Novel aldehyde related radicals were produced via Fenton chemistry and trapped using PBN to form stable adducts that could be analysed via the combined techniques of gas chromatography (GC) and mass spectrometry (MS). The significant findings of this work involve trapping various radicals such as propyl radicals, 2-methyl propyl radicals, butanal radicals (oxoallylic radicals), 2-methyl butanal radicals and methyl radicals in various conformations with PBN and its derivatives and elucidating the fragmentation patterns. The findings have been supported using deuterated isotopologues and PBN derivatives to aid in the understanding of the reaction mechanisms and structures.
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