Simultaneous detection of Ubiquinol-10, ubiquinone-10, and tocopherols in human plasma microsamples and macrosamples as a marker of oxidative damage in neonates and infants

A HPLC-method was developed for the simultaneous detection of the lipophili c antioxidants ubiquinol-10, ubiquinone-10, alpha-tocopherol, and gamma-toc opherol in plasma macrosamples (100 mu l) as well as microsamples (10 mu l) using electrochemical detection with internal standardization (gamma-tocot rienol, ubiquinol-9, ubiquinone-9). The use of a mobile phase containing am monium formate instead of lithium perchlorate as conductivity salt and the use of a PEEK column instead of a steel column improved the reproducibility of the method. The components were separated on a RP C18 column. The detec tion limits for all components were between 1 and 28 fmol. The within-day p recision varied between 3 and 13% for all measured substances. The analytic al recovery was between 93 and 109%. The plasma levels from 10 healthy dono rs were determined in microsamples and macrosamples taken by micropuncture or venous puncture, respectively. A good correlation of the antioxidant lev els for both methods strengthened the reliability and the transferability o f the results, The present method can be used to assess the role of these a ntioxidants in diseases associated with oxidative damage in childhood. (C) 2000 Academic Press.