Potentiometric measurement of H+ concentrations for aluminum orthophosphate titration curves

1980 ◽  
Vol 58 (20) ◽  
pp. 2150-2157
Author(s):  
Donald S. Gamble
Keyword(s):  
Background Noise ◽  
Calibration Procedure ◽  
Glass Electrode ◽  
Data Handling ◽  
Titration Method ◽  
Titration Curves ◽  
Potentiometric Titration Method ◽  
Potentiometric Measurement ◽  
Experimental Errors ◽  
Aluminum Orthophosphate

A potentiometric titration method of measuring accurate H+ concentrations is demonstrated for aluminum orthophosphate solutions. A calibration procedure has been used which permitted the glass electrode to be used as a concentration probe instead of as a quasi-activity probe. The random error "background noise" has been reduced by the use of Fortran computing for chemical calculations, data handling and sorting, and averaging by least squares poly nomial fits. The distribution of experimental errors along the sample titration curve is indicated by estimates for its various regions.

HYDROLYSIS OF CELLULOSE ACETATE SULPHATE IN ACETONE

1954 ◽  
Vol 32 (9) ◽  
pp. 815-822 ◽  
Author(s):  
Karl Keirstead ◽  
John Myers
Keyword(s):  
Acetic Acid ◽  
Cellulose Acetate ◽  
Sulphuric Acid ◽  
Potentiometric Titration ◽  
Titration Method ◽  
Acetate Ester ◽  
Hydrolysis Of Cellulose ◽  
Potentiometric Titration Method ◽  
Hydrolysis Of

When cellulose acetate sulphate is dissolved in acetone the hydrolysis of the sulphate ester is rapid compared with that of the acetate ester. In 70% acetone the relative rates are reversed. Hydrolysis of the sulphate ester in acetone is greatly affected by the temperature. At 25 °C. or greater the hydrolysis is complete after 24 hr. A potentiometric titration method has been developed for the estimation of sulphuric acid in the presence of smaller amounts of acetic acid.

NaCl and CaCl2 activity coefficients in mixed aqueous solutions

1965 ◽  
Vol 20 (6) ◽  
pp. 1332-1336 ◽  
Author(s):  
Edward W. Moore ◽  
James W. Ross
Keyword(s):  
Ionic Strength ◽  
Activity Coefficients ◽  
Technical Assistance ◽  
Osmotic Coefficients ◽  
Electrode System ◽  
Glass Electrode ◽  
Concentration Data ◽  
Harned's Rule ◽  
Potentiometric Measurement

In the investigation of numerous physiological phenomena it is the activity of an ion species which is desired, rather than stoichiometric concentration. The calculation of mean ionic activity from known concentration data requires accurate activity coefficients (ggr). This report concerns the determination of ggrNaCl and ggrCaCl2 in mixed NaCl-CaCl2 solutions by potentiometric measurement with a sodium-selective glass electrode-Ag/AgCl electrode system over the ionic strength range 0.05–0.5 m. Log ggrNaCl varied linearly, at constant total ionic strength, with the ionic strength of CaCl2 in the mixture, in accordance with Harned's rule. From data thus obtained, ggrCaCl2 coefficients in such mixed solutions have been calculated and compared with values calculated from published osmotic data. Resulting activity coefficient curves for ggrCaCl2 are presented over the concentration range encountered in serum and other extracellular fluids. Note: (With the Technical Assistance of Leonard Kaye and Leonard L. Anderson) glass electrodes; ion interaction; electrolyte metabolism; Harned's rule; membrane transport; osmotic coefficients Submitted on March 11, 1965

scholarly journals Composition, stability and stereo effects of zirconium(IV) dl-tartrate formation

2019 ◽  
Vol 57 (2) ◽  
pp. 28-34
Author(s):  
Lilia I. Mukhamedyarova ◽  
◽  
Sergey G. Bezryadin ◽  
Elena Yu. Klukvina ◽  
Vladimir V. Chevela ◽  
...  
Keyword(s):  
Tartaric Acid ◽  
Ph Value ◽  
Acid System ◽  
Alkaline Ph ◽  
Titration Method ◽  
Software Complex ◽  
Tartaric Acids ◽  
Potentiometric Titration Method ◽  
High Concentrations ◽  
Metal Ligand

The system of zirconium (IV) – dl-tartaric acid for metal: ligand 1: 1, 1: 2 and 1: 3 ratios in aqueous solution has been studied by means of using potentiometric titration method in combination with mathematical modeling. The comparison of Bjerrum functions from pH for zirconium(IV) systems: d-tartaric acid and zirconium (IV): dl-tartaric acid, has revealed the following features in the behavior of the curves: the degree of titration for the complexes at a fixed pH value for systems with dl-tartaric acid is more than for d-acid. The CPESSP software complex has calculated the composition, stability constants and molar fractions of zirconium(IV) tartrate accumulation. It has been also found that at a ratio of 1: 1 for Zr (IV) and ligand (H4Tart) ions in the system under study ZrHTart+ is formed, which is tetramerized into Zr4Tart40 and, further, tetranuclear particles of varying degrees of deprotonization are formed, as well as mononuclear forms. In a strongly alkaline pH environment > 10, Bjerrum curves for d- and dl-tartaric acids overlap each other and correspond to hydroxocomplexes of varying degrees of titration. For the 1: 2 ratio, the composition of the complexes for the zirconium(IV) – dl-H4T system is slightly different; compared to the zirconium(IV) – dH4T system, differences are clearly observed for both low and high concentrations. Based on these data, a complex formation scheme in the Zr(IV) – dl-tartaric acid system has been proposed for all the ratios studied. The characteristics of stereoselective diastereomer formation have been calculated. It has been revealed that in the medium of racemic tartrate, ddd- and lll-Zr(H2Tart)2(HTart)3-forms, as well as Zr(H2Tart)(НTart)24-Zr(HTart)35- are formed on a stereoselective basis.

scholarly journals Potentiometric Determination of Minoxidil in Topical Use Pharmaceutical Samples

2018 ◽  
Vol 34 (2) ◽  
pp. 23
Author(s):  
Rogério Adelino De Sousa ◽  
Éder Tadeu Gomes Cavalheiro
Keyword(s):  
Potentiometric Titration ◽  
Confidence Level ◽  
Redox Reaction ◽  
Potentiometric Determination ◽  
Titration Method ◽  
Pharmaceutical Samples ◽  
Chromatographic Procedure ◽  
Potentiometric Titration Method

A potentiometric titration method for the determination of minoxidil based on its redox reaction with K2Cr2O7 is described. The best results were observed using 1.00 x 10-3 mol L-1 K2Cr2O7 and 1.00 x 10-2 mol L-1 minoxidil solutions, and the minoxidil as titrant in 2.00 mol L-1 H2SO4 medium. The method was applied to commercial samples and compared with the results from a chromatographic procedure. Recoveries from 97.4 to 98.7 % were observed depending on the sample. Comparison with the chromatographic procedure reveled agreement within 90% confidence level.

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