Analysis of F2-isoprostanes in plasma of pregnant women by HPLC-MS/MS using a column packed with core-shell particles.

Plasma F2-isoprostanes (F2-isoPs) are reliable biomarkers of oxidative stress. Several possible F2-isoPs are generated by the oxidation of arachidonic acid esterified in phospholipids. The separation of these isomers represents a technical challenge for rapid and selective determination. We have developed a HPLC-MS/MS method for the simultaneous determination of seven plasma F2-isoPs, namely 8-iso-15(R)-prostaglandin F2α (PGF2α), 8-iso-PGF2α, 15(R)-PGF2α, iPF2α-IV, iPF2α-VI, 5-iPF2α-VI, and (±)5-8,12-iso-iPF2α-VI. We have validated this method in plasma of pregnant women, a mild physiological oxidative stress known to increase F2-isoPs. Thus, plasma samples of women collected at the third trimester of pregnancy (n = 20) were subjected to alkaline hydrolysis followed by liquid-liquid extraction in order to extract total F2-isoPs. The F2-isoPs were separated within 16.5 min using a column packed with core-shell particles. The class VI isomers were the most abundant, accounting for 65% of the total level of all quantified F2-isoPs in plasma of pregnant women (P < 0.05). The 15(R)-PGF2α was the most abundant of the class III isomers quantified. This method allowed fast and selective separation of seven isomers from three different classes of F2-isoP regioisomers.