METHOD FOR SEPARATE DETERMINATION OF SACCHAROSE AND PHENYLALANINE Russian patent published in 2013 - IPC G01N31/00 B01D11/00 

FIELD: chemistry.

SUBSTANCE: saccharose and phenylalanine solutions are prepared in a small volume of water, put into a measuring flask and brought up to the volume with a saturated solution of a salting-out agent in form of ammonium sulphate; saccharose and phenylalanine are then extracted by adding acetone to the obtained aqueous salt solution of saccharose and phenylalanine with the volume ratio of the aqueous salt solution of saccharose and phenylalanine to acetone of 20:1; extraction is carried out for 7-10 minutes; after demixing of the system, the aqueous phase is separated from the organic phase; content of saccharose in the aqueous phase is determined from a reaction with potassium dichromate in the presence of sulphuric acid; a photoelectric colorimeter is used to measure optical density of the coloured solution at wavelength 590 nm (thickness of the light-absorbing layer of 1 cm); a calibration curve of optical density of the solution versus concentration of saccharose is plotted; the calibration curve is used to determine concentration of saccharose in the aqueous phase; the organic phase is quantitatively transferred into a cell for potentiometric titration and titrated with 0.01 mol/l KOH solution in anhydrous ethyl alcohol; the indicator electrode is a glass electrode; the comparison electrode used is a silver chloride electrode filled with saturated KCl solution in ethyl alcohol; the electromotive force of the solution is measured on a high-resistance potentiometer; there is a maximum on the differential curve of potentiometric titration which corresponds to content of phenylalanine in the extract.

EFFECT: easier, more reliable and safer analysis.

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