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

1931 ◽  
Vol 15 (2) ◽  
pp. 125-138 ◽  
Author(s):  
David I. Hitchcock
Keyword(s):  
Hydrochloric Acid ◽  
Nitrogen Content ◽  
Sodium Hydroxide ◽  
Isoelectric Point ◽  
Specific Conductivity ◽  
Liquid Junction ◽  
Hydrogen Electrode ◽  
Ph Measurements

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.

scholarly journals THE COMBINATION OF GELATIN WITH HYDROCHLORIC ACID

1929 ◽  
Vol 12 (4) ◽  
pp. 495-509 ◽  
Author(s):  
David I. Hitchcock
Keyword(s):  
Hydrochloric Acid ◽  
Osmotic Pressure ◽  
Concentrated Solutions ◽  
Liquid Junction ◽  
Hydrogen Electrode

1. Cooper's gelatin purified according to Northrop and Kunitz exhibited a minimum of osmotic pressure and a maximum of opacity at pH 5.05 ±0.05. The pH of solutions of this gelatin in water was also close to this value. It is inferred that such gelatin is isoelectric at this pH and not at pH 4.70. 2. Hydrogen electrode measurements with KCl-agar junctions were made with concentrated solutions of this gelatin in HCl up to 0.1 M. The combination curve calculated from these data is quite exactly horizontal between pH 2 and 1, indicating that 1 gm. of this gelatin can combine with a maximum of 9.35 x 10–4 equivalents of H+. 3. Conductivity titrations of this gelatin with HCl gave an endpoint at 9.41 (±0.05) x 10–4 equivalents of HCl per gram gelatin. 4. E.M.F. measurements of the cell without liquid junction, Ag, AgCl, HCl + gelatin, H2, lead to the conclusion that this gelatin in 0.1 M HCl combines with a maximum of 9.4 x 10–4 equivalents of H+ and 1.7 x 10–4 equivalents of Cl- per gram gelatin.

scholarly journals THE SOLUBILITY OF TYROSINE IN ACID AND IN ALKALI

1924 ◽  
Vol 6 (6) ◽  
pp. 747-575 ◽  
Author(s):  
David I. Hitchcock
Keyword(s):  
Hydrochloric Acid ◽  
Sodium Hydroxide ◽  
Ionization Constants ◽  
Distilled Water ◽  
Hydrogen Electrode ◽  
Saturated Solutions

Measurements have been made of the solubility at 25°C. of tyrosine in hydrochloric acid and in sodium hydroxide solutions varying from 0.001 to 0.05 M, and also in distilled water. The pH of the saturated solutions was measured with the hydrogen electrode. The following values for the ionization constants of tyrosine have been obtained from the measurements: kb = 1.57 x 10–12, ka1 = 7.8 x 10–10, ka2 = 8.5 x 10–11. The changes in solubility with pH can be satisfactorily explained by the use of these ionization constants.

scholarly journals THE ISOELECTRIC POINT OF GELATIN AT 40°C

1924 ◽  
Vol 6 (4) ◽  
pp. 457-462 ◽  
Author(s):  
David I. Hitchcock
Keyword(s):  
Hydrochloric Acid ◽  
Sodium Hydroxide ◽  
Osmotic Pressure ◽  
Isoelectric Point ◽  
Ph Values

Measurements have been made at 40°C. of the osmotic pressure and viscosity of 1 per cent gelatin solutions containing varying amounts of hydrochloric acid or sodium hydroxide. Each property was found to exhibit a decided minimum near pH 4.7. In the osmotic pressure experiments the pH of the inside solutions was greater than that of the outside solutions at pH values below 4.7, while it was less than that of the outside solutions at values above pH 4.7. These results indicate that gelatin at 40°C. retains its isoelectric point at about pH 4.7.

scholarly journals Kinetics of Substituted Bis- and Mono-azo Dyes as Corrosion Inhibitors for Aluminium in Hydrochloric Acid and Sodium Hydroxide Solutions

1999 ◽  
Vol 23 (7) ◽  
pp. 408-409
Author(s):  
Loutfy H. Madkour ◽  
R. M. Issa ◽  
I. M. El-Ghrabawy
Keyword(s):  
Hydrochloric Acid ◽  
Sodium Hydroxide ◽  
Azo Dyes ◽  
Thermodynamic Model ◽  
Corrosion Inhibitors ◽  
Kinetics Of ◽  
Alkaline Corrosion

This investigation is designed to apply an advanced kinetic–thermodynamic model on the data obtained from acidic and alkaline corrosion of aluminium using bis- and mono-azo dyes as corrosion inhibitors.

scholarly journals Pretreatment of Wood and Char Samples

Radiocarbon ◽  
1963 ◽  
Vol 5 ◽  
pp. 342-342 ◽  
Author(s):  
Hyman Schultz ◽  
L. A. Currie ◽  
F. R. Matson ◽  
W. W. Miller
Keyword(s):  
Hydrochloric Acid ◽  
Sodium Hydroxide ◽  
Humic Acids ◽  
Large Volume ◽  
Simple Procedure ◽  
Chemical Substance ◽  
Original Material ◽  
Chemical Examination ◽  
Free Sample

It has been shown that contamination from humic acids, chitin, fungal products, etc., contributing young carbon, and from bitumen and carbonate, contributing old carbon, may not be completely removed from wood and char samples by the usual hydrochloric acid and sodium hydroxide pretreatments of the samples. A procedure is offered for the isolation of a pure chemical substance from such samples, cellulose from wood and uncombined carbon from char, that must represent the original material. Cellulose is prepared by boiling the resin-free sample in 1.25% H2SO4 and 1.25% NaOH, adding Schweitzer's reagent, filtering, and precipitating from the filtrate by acidification. Uncombined carbon is separated from char samples as the flocculant precipitate remaining after boiling in 70% HNO3, followed by settling overnight from a large volume of 6M HNO3. A simple procedure for the chemical examination of char samples is also offered for the estimation of the amounts of bitumen, carbonate, combined, and uncombined carbon in char.

scholarly journals DETERMINATION OF ALKALINITY AND DISSOCIATION CONSTANTS OF HIGH SALINITY WATERS: USE OF F5BC TITRATION FUNCTION

2018 ◽  
Vol 35 (2) ◽  
pp. 79
Author(s):  
Bernadete F. Cavalcanti ◽  
Lourdes Cristina Lucena Agostinho ◽  
Luciano Nascimento
Keyword(s):  
Natural Waters ◽  
Dissociation Constants ◽  
A Priori ◽  
Linear Regression Analysis ◽  
Liquid Junction ◽  
Carbonate System ◽  
Ph Measurements ◽  
Apparent Dissociation Constant ◽  
Junction Potential

Measurements of parameters expressed in terms of carbonic species such as Alkalinity and Acidity of saline waters do not analyze the influence of external parameters to the titration such as Total free and associated Carbonic Species Concentration, activity coefficient, ion pairing formation and Residual Liquid Junction Potential in pH measurements. This paper shows the development of F5BC titration function based on the titrations developed by Gran (1952) for the carbonate system of natural waters. For practical use, samples of saline watersfrom Pocinhos reservoir in Paraiba were submitted to titration and linear regression analysis. Results showed that F5BC involves F1x and F2x Gran functions determination, respectively, for Alkalinity and Acidity calculations without knowing “a priori” the endpoint of the titration. F5BC also allows the determination of the First and Second Apparent Dissociation Constant of the carbonate system of saline and high ionic strength waters.

scholarly journals Determination of Uric Acid

1967 ◽  
Vol 13 (1) ◽  
pp. 12-18 ◽  
Author(s):  
H Harold Nishi
Keyword(s):  
Uric Acid ◽  
Hydrochloric Acid ◽  
Sodium Hydroxide ◽  
Serum Sample ◽  
Colorimetric Procedure ◽  
Sodium Hydroxide Treatment

Abstract The Archibald colorimetric procedure for determination of uric acid has been adapted for automation. The major differences from the original manual procedure after sodium hydroxide treatment of the serum sample are neutralization with hydrochloric acid and dialysis of the serum instead of precipitation to remove protein. At the rate of 40 samples per hour, the automated procedure shows good correlation with the manual procedure.

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