Determination of Four Fat-Soluble Vitamins in Vitamin Tablets by Pressurized Capillary Electrochromatography with UV Detection

An effective, convenient and fast method for the analysis of fat-soluble vitamins in vitamin tablets was developed using pressurized capillary electrochromatography(pCEC) with ultra violet(UV) detection. The separations was performed on a reversed-phase C18 capillary column with a certain detection wavelength-time program. The mobile phase was 95%(V/V) methanol containing 0.05% TFA(pH 3.3) at a flow rate of 0.2 mL/min with a separation voltage of 15 kV. Four fatsoluble vitamins(vitamin A, vitamin D3, vitamin E, and vitamin K3) were baseline separated within 5 min in an isocratic pCEC mode. The detection limits for vitamin A, vitamin D3, vitamin E, and vitamin K3(RSN = 3) were 1.5, 3.0, 15 and 1.5 μg/mL with good linearity, respectively. The interference on the analysis of vitamin tablets was effectively eliminated. The recoveries of spiked fat-soluble vitamin samples were 90.0%–110.0% with RSD ranging from 0.53% to 5.46%. This method is simple, rapid, repeatable and accurate.