Analysis of F2-isoprostanes as indicators of non-enzymatic lipid peroxidation in vivo by gas chromatography-mass spectrometry: development of a solid-phase extraction procedure.
Recently, it has been reported that a series of prostaglandin F2-like compounds (F2-isoprostanes) are produced in vivo during peroxidation of arachidonic acid by a mechanism independent of the cyclooxygenase pathway. Of these, 8-epi-PGF2 alpha is shown to be a potent vasoconstrictor. We describe an improved method for analysing F2-isoprostanes in biological fluids. The method involves solid-phase extraction on an octadecylsilane (C18) and an aminopropyl (NH2) cartridge. After conversion to pentafluorobenzyl ester and trimethylsilyl ether derivatives, F2-isoprostanes are analysed by negative-ion chemical ionization mass spectrometry using tetradeuterated PGF2 alpha as the internal standard. The limit of detection of the assay was 10 pg/ml, with a coefficient of variation ranging from 9.4 to 15.1%. Analysis of plasma samples from healthy volunteers (n = 7) revealed no quantifiable levels of free (unesterified) 8-epi-PGF 2 alpha. However, the plasma samples contained 58 to 166 pg/ml of 8-epi-PGF2 alpha when analyzed for the total (sum of free and esterified) F2-isoprostanes. The main advantages of the method lie in the improved recovery, gas chromatographic separation and speed compared to existing techniques.
Nourooz-Zadeh
J
J
Department of Medicine, University College London, UK.
Gopaul
N K
NK
Barrow
S
S
Mallet
A I
AI
Anggård
E E
EE
D003903:Deuterium; D015237:Dinoprost / Q000031:analogs & derivatives* / Q000032:analysis* / Q000097:blood; D004951:Esterification; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006801:Humans; D015227:Lipid Peroxidation; D008077:Lipoproteins, LDL / Q000032:analysis; D012821:Silanes
D008077:Lipoproteins, LDL; D012821:Silanes; C024779:octadecylsilane; C075750:8-epi-prostaglandin F2alpha; D003903:Deuterium; D015237:Dinoprost