Rearrangement of 5S, 12S-dihydroxy-6,8,10,14-(E,Z,E,Z)-eicosatetraenoic acid during gas chromatography: formation of a cyclohexadiene derivative.
The 5S, 12S-dihydroxy-6,8,10,14-(E,Z,E,Z,)-eicosatetraenoic acid, a product of double dioxygenation of arachidonic acid by lipoxygenases, undergoes severe decomposition during gas chromatography-mass spectrometric (GC-MS) analysis of the trimethylsilyl ether methyl ester derivative. The decomposition product was studied by GC-MS and identified as a cyclohexadiene derivative of the parent compound formed by ring closure at C6 and C11. Under identical GC conditions, two stereoisomers, i.e. 5S,12R-dihydroxy-6,8,10,14-(Z,E,E,Z)-eicosatetraenoic acid (leukotriene B4), and 6-trans-leukotriene B4 showed excellent chromatographic properties. These data indicated that the 5,12-dihydroxy derivative of arachidonic acid carrying the trans-cis-trans triene unit selectively undergoes cyclization during GC. These studies also provided an explanation to the controversial GC-MS data reported for this lipoxygenase product.
Borgeat
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P
Inflammation and Immunology-Rheumatology Research Unit, Centre Hospitalier de l'Université Laval, Ste-Foy, Quebec, Canada.
Pilote
S
S
D002849:Chromatography, Gas; D003500:Cyclization; D004355:Drug Stability; D008401:Gas Chromatography-Mass Spectrometry; D006358:Hot Temperature; D006893:Hydroxyeicosatetraenoic Acids / Q000032:analysis*
D006893:Hydroxyeicosatetraenoic Acids; C031911:20-carboxyleukotriene B4