(1) The Determination of Hydrogen Ions: an Elementary Treatise on the Hydrogen Electrode, Indicator and Supplementary Methods, with an Indexed Bibliography on Applications (2) Der Gebrauch von Farbenindicatoren: ihre Anwendung in der Neutralisation-analyse und bei der colorimetrischen Bestimmung der Wasserstoffionenkonzentration

Nature ◽  
1924 ◽  
Vol 113 (2831) ◽  
pp. 157-158
Keyword(s):  
Hydrogen Ions ◽  
Hydrogen Electrode

scholarly journals THE INFLUENCE OF SALTS UPON THE IONISATION OF EGG ALBUMIN

1927 ◽  
Vol 8 (6) ◽  
pp. 543-599 ◽  
Author(s):  
S. P. L. Sørensen ◽  
K. Linderstrøm-Lang ◽  
Ellen Lund
Keyword(s):  
Experimental Determination ◽  
Ammonium Chloride ◽  
Salt Concentration ◽  
Hydrogen Ion ◽  
Hydrogen Ions ◽  
Egg Albumin ◽  
Ion Activity ◽  
The Mean ◽  
Acids And Bases

Introduction. A description is given of the principle followed in the experimental determination of the ionisation of egg albumin, its capacity to combine with acids and bases. Egg albumin is regarded as an ampholyte, and in accordance with J. N. Brønsted's definition of acids and bases, ampholytes are considered as substances capable of both taking up and giving off hydrogen ions. The theoretical treatment of the capacity of ampholytes to combine with acids (and bases) has been carried out on this basis. Section A. Several experimental series are noted, comprising the determination of the activity coefficient of the hydrogen ion (fH) in ammonium chloride solutions of different concentration. Section B. The general method of experimental determination of the ionisation (capacity to combine with adds and bases) of egg albumin in ammonium chloride and potassium chloride solutions is briefly described, and the results of the experiments are compared. Section C. 1). In a brief theoretical survey we have suggested that distinction should be made between isoelectric and isoionic reaction of an ampholyte, the former defined as the hydrogen ion activity (value of paH) at which the mean valency of the ampholyte is 0, the latter as the hydrogen ion activity at which the quantity of acid or base combined with the ampholyte is 0; or, as we prefer to express it, the hydrogen ion activity at which the specific hydrogen ionisation of the ampholyte is 0. If the ampholyte does not combine with other ions than the hydrogen ion, then isoelectric and isoionic reaction coincide. Isoionic reaction is determined by acid-combining experiments. The principle of this determination is briefly described. A theoretical investigation of the alteration with salt concentration of both isoelectric (isoionic) reaction and the shape and direction of the ionisation curves is made, with regard to ampholytes capable only of combining with hydrogen ions, on the basis of the Debye-Hückel formulæ and Linderstrøm-Lang's theory for the ionisation of polyvalent ampholytes of simple type. It is shown that the salt effect, in accordance with the theory, and in qualitative agreement with the experiments, consists in a turning of the ionisation curves, indicating the relation between the quantity of combined acid (specific hydrogen ionisation) and paH, and the turning of the curves, which leaves the isoelectric reaction unaltered, tends in such a direction that the quantity of combined acid at constant ampholyte concentration and constant pan increases with increasing salt concentration. The possibility of chemical combining of other ions than the hydrogen ion is discussed. 2). Following on 1), a brief survey of the experimental results is given. 3). The isoionic reaction is found from the experimental material and proved to be independent of the ammonium chloride concentration. As the mean of all determinations we have paH0 = 4.898 (isoionic reaction). The difference between this value and that formerly found for ammonium sulphate solutions (4.844) is discussed. 4). Finally, on the basis of the theory in Section 1), some simple calculations of the ionisation curves for egg albumin are made, and it appears that the theory can reproduce the experimental results in a rough quantitative way when we assume that the egg albumin has a radius of 2.21·10–7 cm. (answering to a molecular weight of 35,000 in aqueous solution), and contains 30 acid and base groups.

Determination of Hydrogen Ions

1924 ◽  
Vol 77 (4) ◽  
pp. 461-462
Author(s):  
C. A. Shull
Keyword(s):  
Hydrogen Ions

A NEW HYDROGEN ELECTRODE AND APPARATUS FOR THE DETERMINATION OF PH

Science ◽  
1932 ◽  
Vol 75 (1955) ◽  
pp. 643-644 ◽  
Author(s):  
P. L. Du Nouy
Keyword(s):  
Hydrogen Electrode

scholarly journals Coulometric titrations of bases in propylene carbonate and γ-butyrolactone using hydroquinone as the depolarizer and a quinhydrone indicator electrode

2000 ◽  
Vol 65 (8) ◽  
pp. 587-593 ◽  
Author(s):  
Lj.N. Jaksic ◽  
R.M. Dzudovic ◽  
R.P. Mihajlovic ◽  
Z.D. Stanic
Keyword(s):  
Propylene Carbonate ◽  
Platinum Electrode ◽  
Indicator Electrode ◽  
Hydrogen Ions ◽  
Organic Bases ◽  
Oxidation Potentials ◽  
End Point Detection ◽  
Point Detection ◽  
Current Potential

The application of hydroquinone for the coulometric generation of hydrogen ions in propylene carbonate (PC) and ?-butyrolactone (GBL) is described. The current-potential curves recorded for this depolarizer, titrated bases, indicator and the solvents used showed that the investigated depolarizer is oxidized at lower potentials than the oxidation potentials of other components in the solution. The hydrogen ions generated by the oxidation of hydroquinone were used for the titration of organic bases (triethylamine, n-butylamine, pyridine, quinoline, aniline, N,N'-diphenylguanidine, piperidine, and 2,2?-bi?pyridine) in PC and GBL with with visual (Crystal Violet as indicator) and potentiometric end-point detection using a quinhydrone electrode as the indicator electrode. The quinhydrone added to the to be analyzed solution served both as a source of hydrogen ions and, together with the immersed platinum electrode, as a quinhydrone electrode. The relative error of the determination of the bases was about 1%.

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