The Separation Behavior Of Amino Acids In Aqueous Two-Phase Systems Containing Ethanol And Hydrogen Phosphate Dipotassium

Hydrophilic organic solvents / inorganic salt containing aqueous two-phase system isone of moderate separation systems, which can be applied to the fields of biochemicalengineering, and the seperation of metal and complex compound respectively, the extractionof the effective elements in Chinese traditional medicine and the separation of organiccompounds. It is a simple promising separation system with abundant and inexpensive rawmaterial, low toxicity, non-emulsification advantages and may be applied to industry field.At 298±1K, the behavior of forming two phases and the characters of liquid-liquidequilibrium in aqueous two-phase of ethanol and dispotassium hydrogen phosphate werestudied and the partitioning behavior of five single amino acids and mixed amino acids wereinvestigated in these systems. The main contents are as following:1. In the condition of 298±1K, the phase maps of ethanol and dispotassium hydrogenphosphate with different pH values were mapped, and the effect of pH of the phosphatesolutions was investigated, with the increase of pH value, two of the district is graduallyincreasing, as is easy, it cann't form two liquid-liquid system when pH value is less than 6.5. 2. The phase parameters of the systems were determined, such as the composition,density and refractive index. It was found that more ethanol is contained in top phase andmore dispotassium hydrogen phosphate is contained in bottom phase, liquid-liquidequilibrium is finished in 1 minute. These experimental data and phase pictures are valuableto the preparation and extraction material using of ethanol and dispotassium hydrogenphosphate system.3. The distribution behavior of five different polarity, different chain structure of theamino acid (Glutamic acid, Cysteine, Phenylalanine, Lysine, Arginine) in aqueous two-phaseof ethanol and dispotassium hydrogen phosphate was studied fist ,and the influences ofconcentration of dispotassium hydrogen phosphate, pH value, concentration of ethanol,temperature and chain structure of amino acids on the distribution coefficients of the aminoacids were discussed. Finally,it was found that pH value and chain structure of amino acidsimpact on the distribution of amino acids evidently to the most.4. The separation behavior of five mixed amino acids in aqueouse two-phase of ethanoland dispotassium hydrogen phosphate was studied fist. In the condition ofgradient elution, theconcertration of amino acids was determined by HPLC with pre-column 2,4-dinitrofluorobenzne(DNFB) derivation. The best aqueous two-phase systems of separationPhenylalanine and Cysteine from five mixed amino acids was chosen .This simple, accessible,low-cost hydrophilic organic solvents and inorganic salt aqueous two-phase systemprovide a possibility for separating mixed amino acids, it could also be used to forecastsurface structure of the protein containing the amino five elements partitioning behavior ofthis aqueous two-phase system.