HPLC method for simultaneous determination of retinol, α-tocopherol and coenzyme Q10 in human plasma

A simple HPLC method with UV detection is proposed for the simultaneous determination of three lipophilic vitamins: all-trans-retinol, α-tocopherol and coenzyme Q10 (ubiquinone) in human plasma. The following chromatographic conditions were used: RP-18 column, a mobile phase consisted of methanol – n-hexane 72:28 (v/v) and UV detector set at 324, 292 and 276 nm for all-trans-retinol, α-tocopherol and coenzyme Q10, respectively. The linearity range was 0.35–70 μM for all-trans-retinol, 0.23–44 μM for α-tocopherol and 0.12–23 μM for coenzyme Q10. Deproteinised plasma samples were extracted with n-hexane prior to the analysis. The within-day and between day reproducibilities were 1.5 and 3.7% for all-trans-retinol, 4.0 and 5.8% for α-tocopherol and 2.3 and 3.1% for coenzyme Q10, respectively. Using the proposed method the following recoveries were achieved: 91% for all-trans-retinol, 86% for α-tocopherol and 88% for coenzyme Q10. The method was applied to the determination of the levels of retinol, tocopherol and coenzyme Q10 in plasma of healthy children and children treated by elimination diet.