METHOD FOR SEPARATE DETERMINATION OF VITAMINS B AND B IN AQUEOUS SOLUTION Russian patent published in 2011 - IPC C07H23/00 G01N21/78 

FIELD: chemistry.

SUBSTANCE: water-salt mixture of vitamins B₁ and B₁₂ is prepared, for which the analysed vitamin solutions with pharmacopoeial purity are put into a measuring flask, while stirring, brought to the mark using a saturation solution of a salting-out agent in form of ammonium sulphate. The vitamins are extracted with chemically pure isopropyl alcohol by adding to the obtained water-salt mixture of vitamins isopropyl alcohol in volume ratio of the water-salt mixture of vitamins to isopropyl alcohol equal to 20:1, extracted for 5-7 minutes and after stratification of the system, the aqueous phase is separated from the organic phase. Optical density of the water-salt mixture is measured on a UV spectrophotometre at wavelengths 246 nm and 360 nm (thickness of the light-absorbing layer equal to 1 cm). Molar concentration of vitamins B₁ (C_B1) and B₁₂ (C_B12) is calculated using equations: C_B1=6.17·10^-5·A₂₄₆-4.21·10^-5·A₃₆₀ C_B12=3.36·10^-5·A₃₆₀, where A₄₂₆ and A₃₆₀ are optical density of the solution of mixtures of vitamins B₁ and B₁₂ at 246 nm and 360 nm, respectively.

EFFECT: rapid analysis and possibility of almost complete extraction of vitamin B₁₂ from a water-salt mixture during single extraction.

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