Malonaldehyde determination in tissues and biological fluids by ion-pairing high-performance liquid chromatography

A method for the analysis of malonaldehyde by ion pairing high-performance liquid chromatography is described. The method is direct; no thiobarbiturate chromogen formation is required, and sample preparation is simple. After deproteinization with 50% ethanol and removal of particulate by centrifugation samples were passed through a small silica amino column to remove contaminants. Diluted samples (20 microL) were injected onto an octadecylsilane column (25 cm x 4.6 mm ID, 5 micron) which is eluted with 30 mM sodium phosphate buffer, pH 6.5 containing 30% ethanol and 1 mM tetradecyltrimethylammonium bromide. Detection was accomplished by monitoring absorbance at 267 nm. The lower limit for reliable quantification was 5 pmol per injection. The method has been successfully applied to the quantification of malonaldehyde present in plasma, urine and tissues of rats kept under different dietary conditions as well as after in vivo treatment with CCl4 and iron-dextran. The method was also applied to the quantification of malonaldehyde during liver microsomal lipid peroxidation and was compared to the thiobarbituric acid test.