Swine tissues were used as surrogates for human tissues with coenzyme Q10 (CoQ10) as the primary endogenous quinoid to establish a reliable method for the analysis of total CoQ10 concentration and redox status using the reduced and oxidized forms of CoQ9 as internal standards. Specimens of frozen swine tissues were disrupted by bead milling using 2-propanol as the homogenization medium supplemented with the internal standards. After hexane extraction, CoQ10 was analyzed via high-performance liquid chromatography with electrochemical detection. The method is linear (12-60 mg fresh muscle tissue/sample), sensitive (~200 pmol CoQ10/sample), and reproducible (coefficients of variation of 6.0 and 3.2% for total CoQ10 and 2.4 and 3.2% for the redox status of within-day and day-to-day precision, respectively), with analytic recoveries for ubiquinone-10, ubihydroquinone-10, and total Q10 of 91, 104, and 94%, respectively. The concentration and redox status were stable for at least 3 months at -84°C. The total CoQ10 concentrations (pmol/mg fresh tissue) in swine tissues were as follows: lung (17.4±1.42), skeletal muscle (26.7±2.57), brain (40.7±4.02), liver (62.1±31.0), kidney (111.7±37.08), and heart muscle (149.1±36.78). Significant tissue-specific variations were also found for the redox status (% oxidation of total): swine liver (~28), lung (~36), kidney (~37), heart muscle (~57), skeletal muscle (~61), and brain (~67).
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