THE DETERMINATION OF CHOLINE IN VITAMIN PREPARATIONS, INFANT FORMULA AND SELECTED FOODS BY CAPILLARY ZONE ELECTROPHORESIS WITH INDIRECT ULTRAVIOLET DETECTION

A method for the determination of choline in vitamin preparations, inf ant formula and selected foods by capillary zone electrophoresis with indirect ultraviolet detection al 214 nm is described. The ''free'' ch oline in the vitamin preparations was simply extracted with water, the solutions filtered and analysed. The ''free'' and ''bound'' choline i n the other products was extracted with methanol. The near dry extract was then treated with hot saturated aqueous calcium hydroxide to hydr olyse the ''bound'' choline before analysis, A 75 cm X 75 mu m uncoate d fused silica capillary column with an electrolyte consisting of 5 mM 1-methylimidazole, pH 4.5, and an operating voltage of 30 kV was used for all of the determinations. Using these conditions, choline migrat es in less than 3 mill and is well separated from the other components in the electropherograms. The tetramethylammonium ion was used as the internal standard, ?he instrument repeatability data for area calcula tion and migration time variation were goad (coefficient of variation, CV, area calculation 1.4%, n = 10; CV for migration time variation 1. 0%, n = 20). The level of detection for choline using this procedure i s 5 mg/100 g.