An original MEEKC method for the determination of coenzyme Q10 in food supplements

Coenzyme Q10 (2,3-dimethoxy-5-methyl-6-decapremyl-1,4-benzoquinone, CoQ10), also known as ubiquinone (Fig. 1), is a lipid-soluble benzoquinone with a long isoprenyl chain. CoQ10 can accept either one electron, turning into a semiquinone radical (∙QH), or two electrons, turning into the completely reduced form (QH2, ubiquinol). Its electron-exchange activity makes CoQ10 one of the major antioxidant systems found in the human body; for the same reason, is also often included in the formulation of food supplements. The aim of this research is the development of an original micro emulsion electrokinetic chromatography (MEEKC) method for CoQ10 analysis. The electrophoretic conditions used in the preliminary tests involve the use of an uncoated silica capillary (total length 48.5 cm, 75 μm i.d.), a weakly basic BGE containing SDS, and an ultraviolet detection. The stock solution of CoQ10 is prepared in acetone, protected from light and stored at -20°C. The extraction from nutritional supplements is carried out by treatment with an acetonitrile/acetone mixture. The proposed method has proved to be fast and feasible and seems to be suitable for CoQ10 analysis in the quality control of food supplements.