Large-scale density gradient electrophoresis. II. a simple experimental technique securing perfectly stable zones and full utilization of the separation capacity of a density gradient column.

A 140

Journal

of Electroanalytical

Chemistry

Special apparatus is not needed and speed and accuracy various fractions are improved. Examples of applications to different cases are given.

Vol. 1

in the evaluation of the

Ca. Cas.

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LARGE-SCALE DENSITY GRADIENT ELECTROPHORESIS. II. A SIMPLE EXPERIMENTAL TECHNIQUE SECURING PERFECTLY STABLE ZONES AND FULL UTILIZATION OF THE SEPARATION CAPACITY OF A DENSITY GRADIENT COLUMN. Harry Svensson and Erkki Valmet. Science Tools, 6 (1959) 13. This technique for creating a density gradient uses a device which couples in series 2 closed mixing chambers, the second of which contains the sample to be fractionated. In this manner it is possible to obtain the initial zone and the whole density column in the same operation; moreover the need for trial runs and for personal skill is avoided. Since it is possible to choose conveniently the initial concentrations, as well as the volumes of the 2 mixing compartments, many experimental needs can be satisfied. The zones in the column are made perfectly stable, thus ensuring that the method can be used for large scale fractionation (samples up to 500 mg can be fractioned into 8 components using a 250 ml column). Equations for obtaining suitabie values for the initial concentrations and for the volumes of the mixing chambers are given. Ca. Cas. [459 1 ELECTROMIGRATION OF IONS ABSORBED BY FILTER PAPER. R. A. Bailey and L. Yoffe. (Radiochemical Laboratory, Dept. of Chemistry, McGill University, Montreal, Canada.) Can. J. Chem., 37 (1959) 1527. The variation with absorbance of the zone mobilities and obstructive factors for a number of inorganic ions has been investigated in acetic acid and in ammonium hydroxide at several concentrations. The results agree with the form of the semi-empirical equation of Crawford and Edward. For a given ion the apparent zone mobility remains fairly constant obstructive factor, defined as papp = free soln mobilitv’ as the concentration of the background electrolyte is changed except in the very dilute region. However, the apparent obstructive factor varies with the ion and the background electrolyte indicating that specific effects which are not considered in the’equation are important. D. S. Ru. [4'331 ELECTROPHORETIC SEPARATION AND QUANTITATIVE DETERMINATION OF DYESTUFFS. S. Krauze and L. Piekarski. (Dept. of Food Investigation, Academy of Medicine, Warsaw, Poland. ) Acta Pharm. Polon. , 16 (1959) 395. Paper electrophoresis was applied for the separation and identification of food dyestuffs in cases where chromatographic separation had been used without success. The apparatus used was very simple. The separated dyestuffs were determined by direct photometry of the paper strips or by elution and subsequent colorimetric determination. Ad. Hu. [46Il HIGH-VOLTAGE PAPER ELECTROPHORESIS OF ORGANIC ACIDS AND DETERMINATION OF MIGRATION RATES. D. Gross. (Tate and Lyle Research Lab. , Keston, Kent, Great Britain.) Chemistry & Industry, (1959) 1219. The electrophoresis ferent conditions:

of 56 organic acids has been carried

out under three dif-