Quantification of urinary 8‐iso‐prostaglandin F _2α using liquid chromatography–tandem mass spectrometry during cardiac valve surgery

Abstract

Oxidative stress is an unavoidable event during many complex surgical procedures. 8‐iso‐prostaglandin F _2α (8‐iso‐PGF _2α) is a reliable biomarker for the evaluation of oxidative stress in vivo. The aim of this study is to develop simple and accurate liquid chromatography–tandem mass spectrometry (LC‐MS/MS) methods for the detection of urinary 8‐iso‐PGF _2α in samples collected from patients who received a cardiopulmonary bypass (CPB) during cardiac valve surgery. Urine samples of 14 patients with cardiac valve diseases were collected before, during, and after CPB. The level of 8‐iso‐PGF _2α was detected via selected‐reaction monitoring triple quadrupole MS/MS and the result was compared with 12 healthy volunteers. The method's detection limit (3S/N) was 0.25 pg for 8‐iso‐PGF _2α, with a linear working range of 0.25–20 ng/ml. For patients with cardiac valve disease, the 8‐iso‐PGF _2α levels before the bypasses were the same as those of healthy individuals ( P>0.05) and the 8‐iso‐PGF _2α levels during and after CPB were significantly higher than those before the bypasses ( P<0.05). In conclusion, we present a simple and specific protocol for LC‐MS/MS quantification of urinary 8‐iso‐PGF _2α collected during CPB. Using this technique, it would be feasible to assess the levels of oxidative stress during cardiac surgery and thereby helpful for the management of oxidative injury. J. Clin. Lab. Anal. 24:237–245, 2010. © 2010 Wiley‐Liss, Inc.