Spectrophotometric method for the determination of Vitamin A and E using Ferrozine-Fe(II) complex

A simple and sensitive flow injection Spectrophotometric method is reported for the determination of vitamin A and E using Ferrozine-Fe(II) detection system. In the presence of vitamin A/E, Fe(III) reduces. The in situ reduced ions are then reacted with Ferrozine to make a magenta colored complex, which is monitored at absorption wavelength of 562 nm. Vitamin A shows a linear calibration graph in the concentration range of 0.1-10 μg/mL with a limit of detection (3s) of 0.06 μg/mL. The coefficient of determination was r2=0.9974 with relative standard deviations (n = 4) in the range of 0.8-2.8%. The proposed method allowed 10 injections per hour. Vitamin E gives a calibration graph linear in the concentration range of 0.1-20 μg/mL with a limit of detection (3s) of 0.03 μg/mL. The coefficient of determination was r2=0.9993 with relative standard deviations (n = 4) in the range of 1.1- 2.6% with a sample throughput of 30 injections per hour. The method was applied to determine both vitamins in pharmaceuticals, infant milk and blood serum samples using hexane extraction. The method is validated by comparing with HPLC reference method. The calculated results showed that there is no significant difference between the two methods at 95% confidence level.