Patent GB-644382-A (GB)
Title: Improvements in or relating to the fractionation of the components of a mixture in solution
IPC: B01J47/00
Filed: 1947-05-29
Abstract: The components of a mixture in solution consisting at least in part of organic solutes of biological origin, e.g. amino acids, amino-sugars and their derivatives, are fractionated by passing the solution into a column of particulate ion-exchange material wherein the components or ions, acidic or basic, that are reactive to the ion-exchanger are absorbed or combined, while components or ions of opposite character to those absorbed, or electrically neutral substances, flow out with the solvent, and then displacing the components out of the column in turn by introducing a single developer consisting of a solution of a substance which is more strongly bound by the ion-exchanger than any of the components to be displaced.  The components and the developer, due to their differing affinites for the ion-exchanger, arrange themselves in the column in decreasing order of affinity, one component displacing another as more developer is introduced.  In order to separate the fractions as they are discharged, one or more of the physical properties, e.g. electrical conductivity, hydrogen ion concentration or refractive index, of the effluent may be continuously determined. Alternatively, the effluent may be divided into a large number of fractions of equal volume, samples of which are subjected to physical or chemical analysis. As the ion-exchanger, synthetic resins having basic or acidic functions are preferred, and in the separation of strong bases, the cation-exchange resin should not contain an appreciable proportion of free phenolic hydroxyl radicles.  The developer may be an organic or inorganic acid or base.  The solution of the mixture to be fractionated may be an aqueous extract or may contain a proportion of a water-miscible organic solvent, e.g. alcohol or acetone.  Alternatively, waterimmiscible solvents may be employed.  When the solution contains mixed organic and inorganic salts, it may be first passed through a cation-exchange column to remove cations and then through an anion-exchange column to remove acids and when the solution is acid in character the procedure may be reversed.  In examples: (1) creatinine and glycine are separated from aqueous solution using a "Zeo Karb" (Registered Trade Mark) ion-exchange resin and ammonia as the developer; (2) aspartic acid, glycine and histidine are separated from aqueous solution using the ion-exchanger and developer of (1); (3) the amino-carboxylic acids of hydrolysed egg albumen are separated from aqueous solution using the ion-exchange resin of (1) and aqueous caustic soda as the developer, the fractions obtained being subjected to further differentation in another cation-exchange resin column or in a "Deacidite B" anion-exchange resin column in which latter case aqueous hydrochloric acid is employed as developer.  The separation of amino acids from hydrolysed wheat protein and also from hydrolysed salmine and clupeine also are referred to.ALSO:The components of a mixture in solution consisting at least in part of organic solutes of biological origin are fractionated by passing the solution into a column of particulate ion-exchange material wherein the components or ions, acidic or basic, that are reactive to the ion-exchanger, are absorbed or combined, while components or ions of opposite character to those absorbed, or electrically neutral substances, flow out with the solvent, and then displacing the components out of the column in turn by introducing a single developer consisting of a solution of a substance which is more strongly bound by the ion-exchanger than any of the components to be displaced.  The components and the developer, due to their differing affinities for the ion-exchanger, arrange themselves in the column in decreasing order of affinity, one component displacing another as more developer is introduced.  In order to separate the fractions as they are discharged, one or more of the physical properties, e.g. electrical conductivity, hydrogen ion concentration or refractive index, of the effluent may be continuously determined. Alternatively, the effluent may be divided into a large number of fractions of equal volume, samples of which are subjected to physical or chemical analysis.  As the ion-exchanger, synthetic resins having basic or acidic functions are preferred, and in the separation of strong bases, the cation-exchange resin should not contain an appreciable proportion of free phenolic hydroxyl radicles.  The developer may be an organic or inorganic acid or base.  The solution of the mixture to be fractionated may be an aqueous extract or may contain a proportion of a water-miscible organic solvent, e.g. alcohol or acetone.  Alternatively, water immiscible solvents may be employed.  When the solution contains mixed organic and inorganic salts it may be first passed through a cation-exchange column to remove cations and then through an anion-exchange column to remove acids, and when the solution is acid in character the procedure may be reversed.  The process is applicable to the separation of amino-acids, amino-sugars and their derivatives.  In examples (1) creatinine and glycine are separated from aqueous solution using a "Zeo Karb" (Registered Trade Mark) ion-exchange resin and ammonia as the developer; (2) aspartic acid, glycine and histidine are separated from aqueous solution using the ion-exchanger and developer of (1); (3) the amino-carboxylic acids of hydrolysed egg albumin are separated from aqueous solution using the ion-exchange resin of (1); and aqueous caustic soda as the developer, the fractions obtained being subjected to further differentiation in another cation-exchange resin column or in a "Deacidite B" anion-exchange resin column, in which latter case aqueous hydrochloric acid is employed as developer.  The separation of amino acids from hydrolysed wheat protein and also from hydrolysed salmine and clupeine are also referred to.