Rapid and sensitive quantification of 8-isoprostaglandin F2α in human plasma and urine by liquid chromatography-electrospray ionization mass spectrometry

The isoprostane, 8-isoprostaglandin F-2 alpha (8-iso-PGF(2 alpha)), is produced non-enzymatically by direct oxidation of arachidonic acid on the cell surface by oxygen radicals. We developed a new assay method for 8-iso-PGF(2 alpha) using H-2(4)-8-iso-PGF(2 alpha) as the internal standard (I.S.) by high-performance Liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS). For this assay, we established a very simple and rapid pretreatment method using a membrane filter-type solid-phase extraction column (Empore(TM) disk cartridge) for human urine extracts or intact plasma. LC-ESI-MS was performed in the selected ion monitoring (SIM) mode using target ions at mit 353.24 (8-iso-PGF(2 alpha)) and m/z 357.26 (I.S.) with a resolution of 1500. The imprecision for this method was below 13.7%. Mean inaccuracy was 8.7% for added levels of 8-iso-PGF(2 alpha) up to 5000 pg/ml of urine and 500 pg/ml of plasma. Determination of plasma and urinary 8-iso-PGF(2 alpha) concentrations in healthy subjects by the present method revealed that its urinary concentration in smokers tends to be higher than that in nonsmokers. (C) 2000 Elsevier Science B.V. All rights reserved.