METHOD OF DETECTING VITAMIN B IN AQUEOUS SOLUTIONS Russian patent published in 2011 - IPC G01N33/18 C07H23/00 

FIELD: chemistry.

SUBSTANCE: water-salt solution of vitamin B₁₂ with pH 5.3±0.3 is prepared, for which the solution of vitamin B₁₂ with pharmacopoeial purity is put into a measuring flask and saturated with ammonium sulphate solution. Vitamin B₁₂ is extracted with chemically pure isopropyl alcohol, for which the obtained vitamin B₁₂ solution is mixed with isopropyl alcohol in volume ratio of the water-salt solution of vitamin B₁₂ to the organic phase is equal to 20:1. Extraction is carried out in 4-5 minutes until interphase equilibrium is established. After stratification of the system, the aqueous phase is separated from the orgnaic phase and analysed through UV spectrophotometry. A calibration curve of optical density of the water-salt solution versus concentration of vitamin B₁₂ is plotted. Optical density of the water-salt solution is measured in a UV spectrophotometre in a quartz cell 1=1 cm with wavelength 361 nm. Concentration of vitamin B₁₂ in the aqueous phase is determined from the calibration curve.

EFFECT: complete one-time extraction of vitamin B₁₂ from an aqueous solution, reduced labour input, high sensitivity and safety of analysis.

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