Comparative study on the current tools for optimization of stability constants from potentiometric data

Cvetkovski, Aleksandar (2022) Comparative study on the current tools for optimization of stability constants from potentiometric data. In: 3rd European NECTAR Conference, 24-26 Aug 2022, Ljubljana, Slovenia.

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Abstract

Among the participants of COST Action CA18202 NECTAR – Network for Equilibria
and Chemical Thermodynamics Advanced Research, a survey was conducted regarding what
software is used daily and what problems the users are facing. The results show a high
fragmentation in the software used, associated with a common dissatisfaction concerning the
user experience, highlighting the need of the development of new IT tools for the management
of chemical equilibria in solution by the NECTAR community. Following this line, WG4 is
working to meet this need developing a free, multi-platform and open-source software,
dedicated to the analysis of potentiometric data, with the aim of making it become the reference
software for in solution speciation studies. Towards that goal, we have also undertaken a critical
evaluation of the software actually available for the analysis of potentiometric data, in order to
identify the strengths and weaknesses of each and to use this knowledge for the development
of the new IT products. With this aim, the software Hyperquad [1,2], SUPERQUAD [3],
PSEQUAD [4], BSTAC [5], OPIUM [6], ReactlabTM suite [7] and KEV, were tested on an artificial dataset of six different titrations conducted on a hypothetic hexaprotic acid, in order
to optimize the six protonation constants. The results obtained with the different software were
analyzed and discussed. Moreover, the data analysis was carried out including some systematic
errors in the calculation, quite common in the experimental procedures, in order to stress the
impact of systematic errors arising in potentiometry on the refined parameters, and check the
sensitivity of the different software in relation to these errors. The systematic errors considered
were: carbonation of the base used as titrant, impurity of the solution components (partial
salification of the titrated acid, for example), disregarding of the junction potential, the use of
a not correct formal potential, changes on the ionic strength during the titration. The discussion
of the results was also used to highlight the extent of the effects of systematic errors on the final
results and to propose guidelines for the obtention of reliable formation constants.

[1] P. Gans, A. Sabatini, A. Vacca, Talanta 1996, 43, 1739-1753.
[2] http://www.hyperquad.co.uk/HQ2013.htm
[3] P. Gans, A. Sabatini, A. Vacca, Inorg. Chim. Acta 1983, 79, 219-220.
[4] L. Zekany, I. Nagypal, PSEQUAD, a comprehensive program for the evaluation of
potentiometric and/or spectrophotometric equilibrium data using analytical derivatives.
In Computational Methods for the Determination of Formation Constants, D. J. Leggett,
Ed. Plenum Press: New York, 1985, pp. 291-353.
[5] C. De Stefano, P. Mineo, C. Rigano, S. Sammartano, Annali di Chimica (Rome) 1993,
83, 243-277.
[6] https://web.natur.cuni.cz/~kyvala/opium.html
[7] https://jplusconsulting.com/
[8] A.N. Meshkov, G.A. Gamov, Talanta 2019, 198, 200-205.

Item Type:	Conference or Workshop Item (Lecture)
Subjects:	Medical and Health Sciences > Basic medicine Engineering and Technology > Chemical engineering Natural sciences > Chemical sciences Engineering and Technology > Nano-technology
Divisions:	Faculty of Medical Science
Depositing User:	Aleksandar Cvetkovski
Date Deposited:	02 Sep 2022 09:47
Last Modified:	02 Sep 2022 09:47
URI:	https://eprints.ugd.edu.mk/id/eprint/30164

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