Highly Sensitive Electrochemical Sensor for Determination of Vitamin D in Mixtures of Water-Ethanol

This paper describes the electrochemical determination of vitamin D-2 (ergocalciferol) and D-3 (cholecalciferol) in mixed organic/water solvent, using a glassy carbon electrode (GCE). The mixing ratio of organic/water solvent has an important influence on the electrocatalytic response of D vitamins on the surface of the glassy carbon electrode. Well-defined peaks for Vitamin D-2 and D-3 were observed in a 40% ethanol/60% water solution with lithium perchlorate as the support electrolyte. This study demonstrated that the glassy carbon electrode is highly sensitive for the determination of vitamin D-2 and D-3, with a limit of detection of 0.13 and 0.118 mu molL(-1), respectively. No significant interference was seen for vitamins A, E and K in the detection of vitamin D.