Plotting potentiometric titration data using an Apple II

1982 ◽  
Vol 59 (6) ◽  
pp. 519
Author(s):  
Vinay Kumar ◽  
John I. McAndrews ◽  
Jon W. Mauch
Keyword(s):  
Potentiometric Titration ◽  
Titration Data

scholarly journals COMPLEXATION OF GOLD (III) WITH 1-FURFURYLIDENE AMINO-1,3,4-TRIAZOLE AT 288 – 318 K

2017 ◽  
Vol 60 (5) ◽  
pp. 37
Author(s):  
Safarmamad M. Safarmamadov ◽  
Davron A. Muborakkadamov ◽  
Kimyo S. Mabatkadamova
Keyword(s):  
Potentiometric Titration ◽  
Stability Constants ◽  
Least Squares Method ◽  
Slope Angle ◽  
Organic Ligand ◽  
General Stability ◽  
Wide Ph Range ◽  
Titration Data ◽  
Ph Range ◽  
Number Of Particles

The potentiometric titration method was used to determine the ionization constant of 1-furfurylideneamino-1,3,4-triazole (pKk = 11.83 log.). The dominating region of 1-furfurylideneamino-1,3,4-triazoles (FF) was identified in a wide pH range. It was shown that 1-furfurylideneamino-1,3,4-triazole ion (HL+) predominates in the pH range up to 0.5-2.0. At pH of 5.0 to 10.5, the neutral molecule (L) predominates, and at pH>13.0 1-furfurylideneamino-1,3,4-triazolate ion (L-) predominates in a solution. To determine the number of a particles formed during the interaction of Au (III) with FF from the potentiometric titration data the dependence of ΔE on -lg [FF] was used for 1-furfurylideneamino-1,3,4-triazole gold (III) complexes at 288-318 K. The slope of the curves of the ΔE-lg [FF] with the excess of 1-furfurylideneamino-1,3,4-triazole at temperatures of 288, 298 and 308 K is 0.059, 0.060 and 0.061 V/mol/l-1, which corresponds to the sequential addition of three molecules of 1-furfurylideneamino-1,3,4-triazole to gold (III). At the temperature of 318 K it is not possible to find the slope angle corresponding to the tris complex due to a quick change in the potential with an excess of FF in a solution. General stability constants of 1-furfuryldenoamino-1,3,4-triazole complexes of Au (III) according to potentiometric titration data was determined by the Friedman method and non-linear least squares method. It was shown that as the temperature increases, the general stability constants of gold (III) complexes are reduced. It was shown that the introduction of substituents into the 1,2,4-triazole molecule affects both the number of particles formed in a solution and the stability of the complexes. Thus, in the system Au (III) -1,2,4-triazole-H2O at 298 K four complex particles are formed, and in the Au (III) system, 1-furfurylideneamino-1,3,4-triazole-H2O only three are formed. The general stability constants of 1,2,4-triazole complexes equal to lgβ1 = 6.56, lgβ2 = 11.13, lgβ3 = 14.94 and lg4 = 18.78 log units, and for 1-furfurylideneamino-1,3,4-triazole complexes Igβ1 = 5.92, lgβ2 = 10.14, lgβ3 = 13.80 log units. The thermodynamic functions of complexe formation were calculated by the temperature coefficient method. It was shown that all complex particles are enthalpy-stabilized. The greatest increase in the exothermicity of the reactions is observed when a complex of three organic-ligand molecules is formed. The value of ΔS at all steps of complexation is negative, which is most likely due to the decrease in the number of particles in a system under study. The spontaneous reaction of complexation is determined by the enthalpy factorFor citation:Safarmamadov S.M., Muborakkadamov D.A., Mabatkadamova K.S. Complexation of gold (III) with 1-furfurylidene amino-1,3,4-triazole at 288 – 318 K. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 5. P. 37-43.

scholarly journals Complexation between Molybdenum(VI) and Histidine. Least Squares Treatment of Potentiometric Titration Data.

1981 ◽  
Vol 35a ◽  
pp. 233-237 ◽  
Author(s):  
Erik Sylvest Johansen ◽  
Ole Jøns ◽  
V. Romano ◽  
R. Zingales ◽  
Kastriot Spahiu
Keyword(s):  
Least Squares ◽  
Potentiometric Titration ◽  
Titration Data

Re-evaluation of the second thermodynamic dissociation constants of α-alanine, valine, and leucine using potentiometric data measured for aqueous potassium chloride solutions at 298.15 K

2005 ◽  
Vol 83 (1) ◽  
pp. 46-56 ◽  
Author(s):  
Jaakko I Partanen ◽  
Pekka M Juusola ◽  
Virginie Verraes
Keyword(s):  
Amino Acids ◽  
Ionic Strength ◽  
Activity Coefficient ◽  
Potentiometric Titration ◽  
Dissociation Constants ◽  
Ionic Strength Dependence ◽  
Harned Cell ◽  
Titration Data ◽  
Single Ion Activity ◽  
Potentiometric Data

Equations were developed for the calculation of the second stoichiometric (molality scale) dissociation constants (Km2) of α-alanine, valine, and leucine in aq. KCl solutions at 298.15 K from the revised thermodynamic dissociation constants (Ka2) of these acids and the ionic strength (Im) of the solutions. The ionic strength of the solutions considered in this study is determined mostly by KCl alone, and the equations for Km2 were based on the single-ion activity coefficient equations of the Hückel type. The existing literature data obtained from Harned cell measurements and new potentiometric titration data were used to revise the Ka2 values of the three amino acids. The values (1.295 ± 0.013) × 10–10, (1.894 ± 0.009) × 10–10, and (1.685 ± 0.011) × 10–10 were obtained from the new potentiometric titration data for α-alanine, valine, and leucine, respectively. For alanine and valine, the new Ka2 values are also supported by the Harned cell data used, but the value (1.80 ± 0.02) × 10–10 obtained for leucine from these data is significantly different. The potentiometric values are recommended here. The activity coefficient equations for the calculation of Km2 values were also determined from the new potentiometric data. By means of the activity coefficient equations obtained for these three amino acids for KCl solutions, Km2 can be evaluated almost within experimental error up to an Im of about 1.0 mol kg–1. The Km2 values calculated by this method are also compared with the values suggested in the literature.Key words: ionic strength dependence, stoichiometric dissociation constant, Debye-Hückel equation, potentiometry, α-alanine, valine, leucine.

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