Potentiometric Investigation of the Weak Association of Sodium and Oxalate Ions in Aqueous Solutions at 25°C

2005 ◽  
Vol 58 (3) ◽  
pp. 213 ◽  
Author(s):  
Andrew Tromans ◽  
Glenn Hefter ◽  
Peter M. May
Keyword(s):  
Ionic Strength ◽  
Aqueous Solutions ◽  
Infinite Dilution ◽  
Formation Constant ◽  
Ion Pair ◽  
Ion Selective Electrode ◽  
Selective Electrode ◽  
Weak Association ◽  
Tetramethylammonium Chloride ◽  
Good Agreement

The formation constant β(NaOx−) of the extremely weak ion pair formed between sodium (Na+) and oxalate (Ox2−) ions in aqueous solutions has been determined at 25°C as a function of ionic strength in tetramethylammonium chloride by Na+ ion-selective electrode potentiometry. The effects of trace Na+ impurities from all reagents were accounted for. An extrapolated value for β o of 6.6 ± 0.5 M−1 was obtained at infinite dilution, which is in good agreement with literature values. Attempts to measure this constant in 1 M CsCl media gave a β(NaOx−) value of 0.00 ± 0.06 M−1, probably because of competition between Cs+ and Na+ for Ox2−.

Titration of sulphates and lead using lead ion selective electrode

1981 ◽  
Vol 46 (2) ◽  
pp. 368-376 ◽  
Author(s):  
Josef Veselý
Keyword(s):  
Ionic Strength ◽  
Electrode Surface ◽  
Salt Content ◽  
Ion Selective Electrode ◽  
Lead Ion ◽  
Selective Electrode ◽  
Limit Of Determination ◽  
Total Salt Content ◽  
Automatic Titration

Titration of sulphates with lead perchlorate employing lead ion selective electrode indication was studied using additions of various organic solvents at different pH' and ionic strength values. As the optimum emerged systems with 60-70% 1,4-dioxane, pH' 5.3-5.6. After dehydration with sodium hydroxide, dioxane must be freed from the electrode surface-oxidizing impurities by their reduction with sodium metal and subsequent distillation. The method was applied to determination of sulphates in mountain spring waters. Units of ppm can be determined; the limit of determination, however, depends considerably on the content of dioxane, total salt content in the sample, and speed of the semi-automatic titration. Lead can be determined with EDTA in concentrations down to c(Pb2+) = 5 . 10-6 mol l-1.

Association of benflurone in aqueous solutions studied by measuring the activity of chloride ions

1986 ◽  
Vol 51 (11) ◽  
pp. 2437-2443
Author(s):  
František Kopecký ◽  
Mária Vojteková ◽  
Milan Pešák
Keyword(s):  
Aqueous Solutions ◽  
Chloride Ions ◽  
Ion Selective Electrode ◽  
Selective Electrode ◽  
Measured Range

The conventional activity of chloride ions was measured by an ion-selective electrode at 25 °C in aqueous solutions of benflurone, i.e. 5-(2-(N,N-dimethylamino)ethoxy)-7-oxo-7H-benzo(c)fluorene hydrochloride, without or with additions of KCl. These results suggest a gradual association of benflurone; the formation of a hetero-associate, (BH+)2Cl-, followed by higher associates was evaluated in the measured range up to 0.1 mol l-1.

scholarly journals A New method for ISE construction for methyl orange dyes and using for indirect determination of Amitriptyline Hydrochloried drug

2015 ◽  
Vol 12 (1) ◽  
pp. 188-196
Author(s):  
Baghdad Science Journal
Keyword(s):  
Methyl Orange ◽  
Response Time ◽  
Electrode Surface ◽  
Ion Pair ◽  
New Method ◽  
Ion Selective Electrode ◽  
Selective Electrode ◽  
Internal Solution ◽  
Indirect Determination

A new method for construction ion-selective electrode (ISE) by heating reaction of methyl orange with ammonium reineckate using PVC as plasticizer for determination methyl orange and determination Amitriptyline Hydrochloried drug by formation ion-pair on electrode surface . The characteristics of the electrode and it response as following : internal solution 10-4M , pH (2.5-5) ,temperature (20-30) and response time 2 sec. Calibration response for methyl orange over the concentrationrange 10-3 -10-9 M with R=0.9989 , RSD%=0.1052, D.O.L=0.315X10-9 MEre%=(-0.877- -2.76) , Rec%.=(97.230 -101.711) .

Determination of Iodide in Feeds and Plants by Ion-Selective Electrode Analysis

1971 ◽  
Vol 54 (4) ◽  
pp. 760-763
Author(s):  
William L Hoover ◽  
James R Melton ◽  
Peggy A Howard
Keyword(s):  
Ionic Strength ◽  
Solid State ◽  
Necessary Conditions ◽  
Ion Selective Electrode ◽  
Phosphate Solution ◽  
Selective Electrode ◽  
Aoac Method ◽  
Low Levels ◽  
High Concentrations

Abstract A method for determining low levels of iodide in feeds and plants is proposed. The samples are mixed with a 10% phosphate solution to maintain relatively constant ionic strength and pH and analyzed with a solid-state iodide electrode. Ashing is not required and there are no significant interferences by ions commonly found in feeds. The method is accurate in determining iodide content ranging from 10.0 ppm to high concentrations. Necessary conditions for storing and cleaning the electrodes are described. The proposed method is rapid and results compare favorably with AOAC method 7.091.

Influence of extraction properties of PVC plasticizer membrane on the response of coated wire type ion selective electrode

1988 ◽  
Vol 53 (5) ◽  
pp. 912-920 ◽  
Author(s):  
Emil Halámek ◽  
Tomáš Čapoun ◽  
Jan Souček
Keyword(s):  
Distribution Coefficient ◽  
Electrode Potential ◽  
Ion Pair ◽  
Ion Selective Electrode ◽  
Ion Concentration ◽  
Pvc Membrane ◽  
Potential Range ◽  
Selective Electrode ◽  
Coated Wire ◽  
Extraction Properties

The authors studied the influence of the extraction properties of a PVC membrane plasticizer of a coated-wire type ion-selective electrode on its response in titrations of brucine and atropine with sodium tetraphenyl borate, as well as in potentiometric determinations of these compounds. The highest attainable value of the ion pair concentration in the plasticizer, which is limited by the distribution coefficient of the ion pair, determines the interval in which the electrode potential can be changed; and a linear dependence of the potential range of the titration curves on the logarithm of the ion-pair distribution coefficient was found. The slope of the dependence of the electrode potential on the logarithm of the ion concentration to be determined, found in potentiometric measurements, is proportional to the distribution coefficient of the ion which forms a pair with the ion to be determined and in whose solution the electrode membrane is activated between the measurements. The dependence of the slope of the electrode function on the logarithm of the product of the mentioned distribution coefficients is linear.

Cadmium-Isocitrate Complex: Its Stability as a Function of Ionic Strength

1975 ◽  
Vol 30 (9-10) ◽  
pp. 555-561 ◽  
Author(s):  
P. Scoppa
Keyword(s):  
Ionic Strength ◽  
Isocitrate Dehydrogenase ◽  
Infinite Dilution ◽  
Formation Constant ◽  
Chemical Forms

The complexation of cadmium by isocitrate has been studied at 25 °C and pH 7.5 in a range of ionic strength from 0.01 to 0.16. The formation constant of the complex between cadmium and tribasic isocitrate varies from 860 M-1 at μ= 0.16 to approximately 24,500 M-1 at infinite dilution. These data allow the distribution of the chemical forms of cadmium added to the incubation mixtures for the assay of NAD-dependent isocitrate dehydrogenase to be calculated.

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