engleski

TANDEM MASS SPECTROMETRIC ANALYSIS OF AROLYHYDRAZONES DERIVED FROM NICOTINIC ACID HYDRAZIDE

In this work detailed structural analysis of selected aroylhydrazones (Scheme 1), derived from aromatic aldehydes and nicotinic acid hydrazide, was performed by electrospray ionization mass spectrometry (ESI MS) in both positive and negative ion mode. Structural isomers of aroylhydrazones were distinguished by tandem mass spectrometry. The MS/MS spectra and fragmentation pathways of compounds 3 and 4 (derived from 3- and 4-methoxy salicylaldehyde respectively) differ due to enolimino-ketoamino tautomeric interconversion of 3. Compounds 5 and 6 (derived from 3- and 5-chloro salicylaldehyde) were distinguished by MS/MS as a result of ortho effect. Main fragmentation pathway of the 5 was loss of HCl, whereas for 6 the main pathway was loss of HCN. The fragmentation patterns of sodium adduct ions [M+Na]+ of the hydrazones were also investigated since the presence of an alkali metal influences the product-ion spectra.

aroylhydrazones; tandem mass spectrometry; structural isomers

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