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Negative Ion Electrospray Mass Spectrometry of Polyphenols, Catecholamines and their Oxidation Products
Author(s) -
Kerwin James L.
Publication year - 1996
Publication title -
journal of mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1076-5174
DOI - 10.1002/(sici)1096-9888(199612)31:12<1429::aid-jms443>3.0.co;2-i
Subject(s) - chemistry , pyrogallol , quinone methide , mass spectrometry , moiety , tandem mass spectrometry , polyphenol , quinone , organic chemistry , medicinal chemistry , chromatography , antioxidant
Polyphenols, catecholamines and their oxidation products have a variety of physiological effects and are key components of insect cuticle and other biological structures. Three dihydroxybenzene isomers were easily differentiated using negative ion electrospray mass spectrometry (ESMS) or tandem mass spectrometry (MS/MS). Ions at m / z 107–109 were diagnostic for more complex polyphenols and catecholamines with a dihydroxybenzene moiety. The product ion spectra of other compounds including 3,4‐dihydroxyphenylacetic acid, 3,4‐dihydroxyphenylalanine (DOPA) and N‐acetyldopamine (NADA) had product ions at m / z 121–123 corresponding to methylene homologues of dioxygenated benzene. Oxidation of DOPA using tyrosinase, Ag 2 O or NaIO 4 could be followed using ESMS and several proposed intermediates proceeding from DOPA through a quinone methide intermediate, 5,6‐dihydroxyindole and dihydroxyindole quinone were confirmed using negative ion ESMS/MS. Spectra of the NaIO 4 oxidation products of 1,2,3‐trihydroxybenzene (pyrogallol) were consistent with tetrahydroxybenzene, two non‐cyclic tetraoxygenated derivatives and a bicyclic polymerization product, purpurogallin. ESMS can be used to analyze complex polyphenolic conjugates commonly encountered in biological specimens.