A graphical method for locating the end point in potentiometric titration curves

1974 ◽  
Vol 271 (5) ◽  
pp. 344-345 ◽  
Author(s):  
A. M. Wahbi ◽  
S. Ebel ◽  
C. P. Christiansen
1990 ◽  
Vol 68 (5) ◽  
pp. 674-678 ◽  
Author(s):  
Turgut Gündüz ◽  
Esma Kiliç ◽  
Güleren Özkan ◽  
Muhammed F. Awaad ◽  
Mustafa Tastekin

In the present work, 11 aromatic and nine aliphatic carboxylic acids, namely benzoic, 2-nitrobenzoic, 3-nitrobenzoic, 4-nitrobenzoic, 2,4-dinitrobenzoic, 3,5-dinitrobenzoic, 2-aminobenzoic, 3-aminobenzoic, 4-aminobenzoic, o-phthalic, salicylic, formic, acetic, monochloroacetic, dichloroacetic, trichloroacetic, propionic, n-butyric, caprylic, and myristic acids, were titrated conductimetrically and potentiometrically with triethylamine in acetonitrile solvent, under a nitrogen atmosphere, at 25 °C. Closer investigation of the conductimetric titration curves of these acids showed that the acidity of an acid, rather than the basicity of its conjugate base, plays a major part in the formation of homoconjugate ions, at least in acetonitrile solvent. If the acid is strong enough, there is a maximum before the experimental end point at about the half-neutralization point. To determine the minimum strength for an acid to show this maximum before the end point, all acids were also titrated potentiometrically. It was found that those acids which have half-neutralization potentials over −85 mV give a strong homoconjugation reaction and show a maximum before the experimental end point. Moreover, the acids that show maxima before the experimental end point in the conductimetric titration also show rather well-shaped potentiometric titration curves. Keywords: nonaqueous media, conductimetric titrations, potentiometric titrations, titration in acetonitrile, acidity and homoconjugation.


Author(s):  
Diana Spiegelberg ◽  
Jonas Stenberg ◽  
Pascale Richalet ◽  
Marc Vanhove

AbstractDesign of next-generation therapeutics comes with new challenges and emulates technology and methods to meet them. Characterizing the binding of either natural ligands or therapeutic proteins to cell-surface receptors, for which relevant recombinant versions may not exist, represents one of these challenges. Here we report the characterization of the interaction of five different antibody therapeutics (Trastuzumab, Rituximab, Panitumumab, Pertuzumab, and Cetuximab) with their cognate target receptors using LigandTracer. The method offers the advantage of being performed on live cells, alleviating the need for a recombinant source of the receptor. Furthermore, time-resolved measurements, in addition to allowing the determination of the affinity of the studied drug to its target, give access to the binding kinetics thereby providing a full characterization of the system. In this study, we also compared time-resolved LigandTracer data with end-point KD determination from flow cytometry experiments and hypothesize that discrepancies between these two approaches, when they exist, generally come from flow cytometry titration curves being acquired prior to full equilibration of the system. Our data, however, show that knowledge of the kinetics of the interaction allows to reconcile the data obtained by flow cytometry and LigandTracer and demonstrate the complementarity of these two methods.


1969 ◽  
Vol 47 (8) ◽  
pp. 1269-1273 ◽  
Author(s):  
A. L. Beauchamp ◽  
J. Israeli ◽  
H. Saulnier

Cu(II), Ni(II), Co(II), and Zn(II) nitrilotriacetates (MeX−) react with histamine nitrate (LH+) to form a protonated mixed complex MeXLH where the metal appears to be bound only to the tertiary imidazolic nitrogen of histaminium ion. At higher pH values the proton dissociates to yield a mixed complex ion MeXL− in which both the imidazolic nitrogen and the terminal amino group are coordinated. The formation constants of these species were calculated from the potentiometric titration curves.


2006 ◽  
Vol 110 (9) ◽  
pp. 4451-4458 ◽  
Author(s):  
Joanna Makowska ◽  
Katarzyna Bagiñska ◽  
Mariusz Makowski ◽  
Anna Jagielska ◽  
Adam Liwo ◽  
...  

1977 ◽  
Vol 13 (3) ◽  
pp. 213-216 ◽  
Author(s):  
V. S. Luneva ◽  
T. V. Pavlova

1974 ◽  
Vol 46 (9) ◽  
pp. 1362-1364 ◽  
Author(s):  
J. J. Kankare ◽  
P. O. Kosonen ◽  
P. O. Vihera

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