2.4- Dinitrophenylhydrazones core aldehydes

The ozonides of choline and ethanolamine phosphatides and triglycerides can be subjected to reduction with triphenylphosphine to yield the corresponding core aldehydes, and further derivatized to the 2,4-dinitrophenylhydrazones (DNP). The core aldehydes and their DNP derivatives can be separated by HPLC and characterized by various techniques, including EI-MS and TS-MS of positive and negative ions . See also Section VHI.E. 

Dinitrophenylhydrazones (DNP) aldehyde determination, 670 core aldehydes, 689 malondialdehyde determination, 669 ozonide reduction, 726... 

Sevanian et al. (1994) applied GLC and LC/TS/MS for the analysis of plasma cholesterol-7-hydroperoxides and 7-ketocholesterol. Analysis of human and rabbit plasma identified the commonly occurring oxidation products, yet dramatic increases in 7-ketocholesterol and cholesterol-5p, 6P-epoxide were observed. The study failed to reveal the presence of choles-terol-7-hydroperoxides, which were either too unstable for isolation, metabolized or further decomposed. The principal ions of cholesterol oxides monitored by LC/TS/MS were m/z 438 (cholestane triol) m/z 401 (cholesterol-7-hydroperoxide) m/z 401 (7-ketocholesterol) m/z 367 (7a-hydroxycholesterol) m/z 399 (cholesta-3,5-dien-7-one) and m/z 385 (choles-terol-5a,6a-epoxide). The major ions were supported by minor ions consistent with the steroid structure. Kamido et al. (1992a, b) synthesized the cholesteryl 5-oxovaleroyl and 9-oxononanoyl esters as stable secondary oxidation products of cholesteryl arachidonate and linoleate, respectively. These compounds were identified as the 3,5-dinitrophenylhydrazone (DNPH) derivatives by reversed-phase LC/NICI/MS. These standards were used to identify cholesteryl and 7-ketocholesteryl 5-oxovaleroyl and 9-oxononanoyl esters as major components of the cholesteryl ester core aldehydes generated by copper-catalysed peroxidation of low-density lipoprotein (LDL). In addition to 9-oxoalkanoate (major product), minor amounts of the 8, 9, 10, 11 and 12 oxo-alkanoates were also identified among the peroxidation products of cholesteryl linoleate. Peroxidation of cholesteryl arachidonate yielded the 4, 6, 7, 8, 9 and 10 oxo-alkanoates of cholesterol as minor products. The oxysterols resulting from the peroxidation of the steroid ring were mainly 7-keto, 7a-hydroxy and 7P-... 

Sjovall, O., Kuskis, A. and Kalho, H. Tentative identification and quantification of TAG core aldehydes as dinitrophenylhydrazones in autoxidized sunflowerseed oil using reversed-phase HPLC with electrospray ionization MS. Lipids 38,1179-1190 (2003). 

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See also in sourсe #XX -- [ ]

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