An improved procedure for the enrichment of plasma F2- isoprostanes prior to final determination by GC-MS/NICI

One of the most popular approaches to quantify oxidative injury is to measure lipid
peroxidation products and, in particular, F2-isoprostanes (F2-IPs). F2-IPs is a group of prostaglandin
F2-like compounds derived from the non-enzymatic oxidation of arachidonic acid. Of these, the
15-F2t-isoprostane (8-iso-PGF2�) has received considerable attention, because it possesses adverse
biological activities. Previous Gas Chromatographic-Mass Spectrometric (GC-MS) methods for measuring
plasma F2-IPs from this laboratory involved two chromatography steps on C18 and NH2-cartridges.
Problems may, however, arise with chromatography on C18 cartridges, as it can be time-consuming
and losses may occur depending upon the pH and e�ciency of the sample loading. Therefore, it was
decided that the C18 chromatography step be replaced with a single lipid partitioning step and the
NH2-chromatography be simpli�ed. In 70 plasma samples from healthy individuals, total (sum of free and
esteri�ed) 15-F2t-isoprostane concentrations ranged from 0.5 to 3.13 nM. This assay meets all prede�ned
method performances in terms of speci�city and sensitivity. The improved method is suitable for the
analysis of samples from larger clinical trials investigating the role of oxidant injury under conditions
associated with oxidative stress.