High-performance liquid chromatography with electrochemical detection for the simultaneous determination of vitamin A, D3 and E in milk.
A high-performance liquid chromatographic electrochemical detection for the rapid and simultaneous determination of the vitamin A, D3 and E is described. The separation is carried out by using a C18 reversed-phase column and 0.1 M LiClO4 in methanol-water (99:1, v/v) as the mobile phase. The compounds are eluted with good resolution in the above order within about 15 min and are determined by amperometric detection with a glassy carbon electrode at +1050 mV (vs. Ag/AgCl). The method gave reproducible results and the detection limits were of the order of 0.07, 4 and 0.2 ng of vitamin A, D3 and E, respectively. The method was successfully applied to the determination of vitamin A, D3 and E in liquid cow milk and milk powder samples. After saponification, fat-soluble vitamins were extracted with hexane and a methanolic solution of the dried extract was injected directly into the chromatographic system, avoiding the clean-up step that is necessary for vitamin D3 when electrochemical detection is not used. Good recoveries were obtained.
Delgado Zamarreño
M M
MM
Departamento de Química Analítica, Nutrición y Bromatología, Facultad de Química, Universidad de Salamanca, Spain.
Sánchez Pérez
A
A
Gómez Pérez
C
C
Hernández Méndez
J
J
D000818:Animals; D002762:Cholecalciferol / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid; D004563:Electrochemistry; D007202:Indicators and Reagents; D008892:Milk / Q000737:chemistry*; D014801:Vitamin A / Q000032:analysis*; D014810:Vitamin E / Q000032:analysis*
D007202:Indicators and Reagents; D014801:Vitamin A; D014810:Vitamin E; D002762:Cholecalciferol