Formation constants for selected organo—metal (Al3+, Fe3+)—phosphate complexes

1985 ◽  
Vol 63 (12) ◽  
pp. 3357-3366 ◽  
Author(s):  
Paul A. Arp ◽  
W. Lense Meyer
Keyword(s):  
Organic Acids ◽  
Aqueous Solutions ◽  
Reference Electrode ◽  
Formation Constants ◽  
Glass Electrode ◽  
Metal Phosphate ◽  
Electrode Pair ◽  
Phosphate Ions

The possible formation of organo–metal–phosphate complexes (O–M–P) in aqueous solutions is examined by potentiometric titration analysis. The complex-forming solutions contain Al3+-ions or Fe3+-ions, organic acids (salicylic, phthalic, oxalic, and citric acids) and phosphate ions. The titrations are done within the precipitation-free pH-region from 2 to 4.5 (approximately) at 25 °C under nitrogen at an ionic strength of 0.2 M KCl. The calibration of the electrode pair (glass-electrode, calomel-reference electrode) and the determination of the formation constants are facilitated by analyzing the pertinent curves with the ACBA-(Arena etal.) and MINIQUAD-(Gans etal.) computer programs. The results suggest (i) that O–M–P complexes are readily formed, and that the power of selected organic acids to form ternary mixed-ligand complexes with Al3+-ions and phosphate ions decreases in the order salycilate > citrate > oxalate > phthalate. Also, Fe3+-ions are found to be more strongly bound by salicylate and phosphate ions than Al3+-ions. The effect of O–M–P formation on the chemical speciation of Al in buffered aqueous solutions containing mineral nutrients for the growth of biological organisms is demonstrated for a special case study.

Ionization of Water in Concentrated Potassium Halide Media

2000 ◽  
Vol 53 (5) ◽  
pp. 369 ◽  
Author(s):  
Faradj K. Samani ◽  
Stephen G. Capewell ◽  
Pal M. Sipos ◽  
Peter M. May ◽  
Glenn Hefter
Keyword(s):  
Ionic Strength ◽  
Aqueous Solutions ◽  
High Precision ◽  
Excellent Agreement ◽  
Ion Pairs ◽  
Formation Constants ◽  
Glass Electrode ◽  
Ionic Product ◽  
Ionization Of Water ◽  
Potassium Halide

The ionic product of water, pKw = –log[H+][OH–], has been determined as a function of ionic strength (I ) in concentrated aqueous solutions of KCl, KBr and KI at 25˚C by high-precision glass electrode potentiometric titrations. The pKw values obtained are in excellent agreement with, but generally more precise than, literature data. At I > 1 M the pKw values increase smoothly and show systematic differences in the order KCl < KBr < KI, consistent with the decreasing H+-acceptor ability of the medium anions. Analogous behaviour is observed in MCl solutions, with pKw values varying in the order NaCl < KCl < CsCl. Formation constants of MOH0 ion pairs derived from these data are consistent with literature values.

Determination of Sodium in Urine by Specific Ion Electrode

1967 ◽  
Vol 13 (3) ◽  
pp. 227-232 ◽  
Author(s):  
Joseph S Annino
Keyword(s):  
Excellent Agreement ◽  
Reference Electrode ◽  
Sodium Concentration ◽  
Glass Electrode ◽  
Sodium Ion ◽  
Flame Photometry ◽  
Standard Curve ◽  
Sodium Activity ◽  
Ion Activity

Abstract A method has been developed for determination of sodium concentration (activity) in urine using a glass electrode designed to be especially sensitive to sodium ion activity. The urine is diluted 2:20 with Tris buffer (pH 8.0) and sodium activity measured by dipping a sodium electrode and calomel reference electrode in the diluted specimen and obtaining a millivolt reading with a sensitive pH meter. The sodium concentration is then calculated from a predetermined standard curve. Concentrations of 0-200 mEq./L. may be read using the same dilution. Blind comparisons of sodium concentrations obtained by flame photometry and by sodium ion electrode showed excellent agreement.

scholarly journals Determination of Trace Amounts of Hydrofluoric Acid in Non-Aqueous Solutions by the Coulometric Titration Method

Sensors ◽  
2018 ◽  
Vol 18 (12) ◽  
pp. 4439 ◽  
Author(s):  
Cairui Huang ◽  
Congcong Shen ◽  
Ling Jin ◽  
Hongwei Cai
Keyword(s):  
Aqueous Solutions ◽  
Hydrofluoric Acid ◽  
Coulometric Titration ◽  
Accurate Determination ◽  
Ethanol Solution ◽  
Constant Current ◽  
Electrode Pair ◽  
Working Electrode ◽  
Relative Standard

For monitoring of trace amounts of hydrofluoric acid in the organic fluorine chemical industry, a facile method for determination of the hydrofluoric acid in an ethanol solution of lithium chloride, by coulometric titration, was proposed. Relying on homemade acid–base coulometric autotitrator, the electrolyte was 0.50 mol·L−1 LiCl ethanol solution and the constant current intensity was 0.2–2 mA. As for the working electrode pair, a platinum plate was used as a working electrode, and a platinum wire was used as an auxiliary electrode. The indicating electrode was the pH composite glass electrode and the titration endpoint was pH 5.50. The results showed that the relative standard deviation was below 2.0%, as the content of the hydrofluoric acid was between 2 μg to 100 μg. The recovery rate was 99.0–102.0%. This proposed route has the advantages of simplicity, convenience, quickness, accuracy, and automation, which can be applied to the accurate determination of trace amounts of hydrofluoric acid, in non-aqueous solutions.

scholarly journals The measurement and interpretation methodology of resistivity logs affected by the Groningen effect – a Polish case study

2020 ◽  
Vol 46 (1) ◽  
pp. 35
Author(s):  
Stanislaw Baudzis ◽  
Jadwiga A. Jarzyna ◽  
Edyta Puskarczyk
Keyword(s):  
High Resolution ◽  
Reference Electrode ◽  
Well Log ◽  
Standard Measurement ◽  
Resistivity Data ◽  
Resistivity Logs ◽  
History Of ◽  
Formation Resistivity

True formation resistivity Rt measurement is one of the fundamental logs in the calculation of hydrocarbon resources. That is why it is very important to have the most reliable resistivity data possible. In this paper, the various outcomes obtained by Polish well log analysts and engineers for the proper determination of hydrocarbon saturation in the Main Dolomite deposits in the Polish Lowland are presented. The long history of efforts directed to make proper exploitation decisions in wells where the Groningen effect has been observed is illustrated, starting with the standard measurement and interpretational approach, through the modified construction of a reference electrode in a Laterolog device and ending with an examination of HRLA (High-Resolution Laterolog Array) or Array Compensated Resistivity Tool) ACRt results. The processing of resistivity logs with the special Poprawki software is included.

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