THE COMBINATION OF A STANDARD GELATIN PREPARATION WITH HYDROCHLORIC ACID AND WITH SODIUM HYDROXIDE

It has been found possible to obtain constant dry weights of sheet gelatin only by drying in vacuo at temperatures below 100°C. for a period of several weeks. Values are given for the ash and nitrogen content, the specific conductivity, and the isoelectric point of a standard gelatin preparation. By the method of E.M.F. measurements of cells without liquid junction, of the type Ag, AgCl, HCl + gelatin, H₂, it has been found that this gelatin in 0.1 M HCl combines with a maximum of 9.58 x 10^–4 equivalents of H⁺ and 2.0 x 10^–4 equivalents of Cl^-. By means of pH measurements with the hydrogen electrode and a KCl junction, the combination curve of this gelatin with H⁺ from HCl and OH^- from NaOH has been determined between pH 1.1 and 12.5.