Analysis of malondialdehyde in biological matrices by capillary gas chromatography with electron-capture detection and mass spectrometry

A gas chromatographic method is described for the quantification of free an d total malondialdehyde (MDA) in biological materials, The procedure involv es derivatization of the analyte with 2,4,6-trichlorophenylhydrazine, extra ction with n-hexane, and separation of the cyclic derivatization product on a OV-5 gas chromatographic column. Concentration of the derivatization rea gent, pH, reaction time, and temperature were investigated to determine the optimal derivatization conditions. Under these conditions, the method allo ws for the selective detection of free and total MDA at femtomole levels in several biological materials without any interferences. The procedure yiel ds relative standard deviation values for the intra- and interassays in the range 3.3 and 3.9%, respectively, for the electron-capture and mass-select ive (SIM mode) detection systems. Recoveries of MDA from spiked matrices re ached 96%. The present method offers the advantage of the alternative use o f either electron-capture or mass-selective detection, Furthermore it avoid s overestimation of MDA since it employs mild conditions for sample process ing and there is no need for preventing protein separation for the assessme nt of free MDA. (C) 2001 Academic Press.