Studies on reduced and oxidized ubiquinones. I. Simultaneous determination of reduced and oxidized ubiquinones in tissues and mitochondria by high performance liquid chromatography.

Abstract

A high performance liquid chromatographic method with both an ultraviolet spectrometric detector (UVD) and an electrochemical detector (ECD) has been developed for the simultaneous determination of reduced and oxidized ubiquinones in biological materials. This method is based on extraction from animal tissues or mitochondrial fractions with ethanol-n-hexane mixture, followed by quantitation on a reversed-phase column with UVD and ECD. The detection limits by ECD or UVD were 100pg, 2ng, 150pg and 2ng for ubiquinol-9, ubiquinone-9, ubiquinol-10 and ubiquinone-10, respectively. The persentages of reduced ubiquinones (ubiquinols) to total ubiquinones were 41.6, 32.4 and 45.2% for guinea pig heart, rat heart and heart mitochondrial fraction of guinea pig, respectively, with added succinate as a substrate.