Stability studies of ubiquinol in plasma.

Background: Ubiquinol is a sensitive redox marker in the first line of the antioxidative defence mechanism and is increasingly being measured in oxidation studies. Because of its apparent instability during storage and processing, we compared various storage conditions. Method: Blood was collected from three volunteers into tubes containing EDTA; it was then separated at 4°C and cryopreserved with saccharose (final concentration 6 g/L). Aliquots were stored with or without glutathione or butylated hydroxytoluene at -20°C and -80°C. Results and conclusion: Ubiquinol in samples stored at -20°C was not stable; however, it was stable when stored at -80°C, even without addition of antioxidant. By contrast, α-tocopherol was stable under all conditions studied. [ABSTRACT FROM AUTHOR]