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Berto S, Blasco S, Castellino L, Cvetkovski A, De Stefano C, Gama S, García-España E, Hermann P, Lando G, Marafante M, Meyer M, Plass W, Quinodoz L, Milea D. A tutorial on potentiometric data processing. Analysis of software for optimization of protonation constants. Anal Chim Acta 2024; 1303:342476. [PMID: 38609256 DOI: 10.1016/j.aca.2024.342476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 03/11/2024] [Accepted: 03/12/2024] [Indexed: 04/14/2024]
Abstract
Defining the distribution of the chemical species in a multicomponent system is a task of great importance with applications in many fields. To clarify the identity and the abundance of the species that can be formed by the interaction of the components of a solution, it is fundamental to know the formation constants of those species. The determination of equilibrium constants is mainly performed through the analysis of experimental data obtained by different instrumental techniques. Among them, potentiometry is the elective technique for this purpose. As such, a survey was run within the NECTAR COST Action - Network for Equilibria and Chemical Thermodynamics Advanced Research, to identify the most used software for the analysis of potentiometric data and to highlight their strengths and weaknesses. The features and the calculation processes of each software were analyzed and rationalized, and a simulated titration dataset of a hypothetic hexaprotic acid was processed by each software to compare and discuss the optimized protonation constants. Moreover, further data analysis was also carried out on the original dataset including some systematic errors from different sources, as some calibration parameters, the total analytical concentration of reagents and ionic strength variations during titrations, to evaluate their impact on the refined parameters. Results showed that differences on the protonation constants estimated by the tested software are not significant, while some of the considered systematic errors affect results. Overall, it emerged that software commonly used suffer from many limitations, highlighting the urgency of new dedicated and modern tools. In this context, some guidelines for data generation and treatment are also given.
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Affiliation(s)
- Silvia Berto
- Università di Torino, Dipartimento di Chimica, Via P. Giuria 7, 10125, Torino, Italy.
| | - Salvador Blasco
- Institute of Molecular Sciences, Departamento de Química Inorgánica, University of Valencia, C/Catedrático José Beltrán Martínez 2, 46980, Paterna, Valencia, Spain
| | - Lorenzo Castellino
- Università di Torino, Dipartimento di Chimica, Via P. Giuria 7, 10125, Torino, Italy
| | - Aleksandar Cvetkovski
- Faculty of Medical Sciences, Goce Delcev Universit, Krste Misirkov Bb, PO 201, 2000, Štip, Macedonia
| | - Concetta De Stefano
- Università degli Studi di Messina, Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, CHIBIOFARAM, V.le F. Stagno d'Alcontres, 31, 98166, Messina, Italy
| | - Sofia Gama
- Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10 (km 139.7), 2695-066, Bobadela LRS, Portugal
| | - Enrique García-España
- Institute of Molecular Sciences, Departamento de Química Inorgánica, University of Valencia, C/Catedrático José Beltrán Martínez 2, 46980, Paterna, Valencia, Spain
| | - Petr Hermann
- Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 8, 128 40 Prague 2, Czech Republic
| | - Gabriele Lando
- Università degli Studi di Messina, Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, CHIBIOFARAM, V.le F. Stagno d'Alcontres, 31, 98166, Messina, Italy
| | - Matteo Marafante
- Università di Torino, Dipartimento di Chimica, Via P. Giuria 7, 10125, Torino, Italy
| | - Michel Meyer
- Institut de Chimie Moléculaire de l'Université de Bourgogne (ICMUB), UMR 6302, CNRS, Université de Bourgogne, 9 avenue Alain Savary, BP 47870, 21078, Dijon, Cedex, France
| | - Winfried Plass
- Institut für Anorganische und Analytische Chemie, Friedrich Schiller University Jena, Humboldtstr 8, D-07743, Jena, Germany
| | - Lauryn Quinodoz
- Institut de Chimie Moléculaire de l'Université de Bourgogne (ICMUB), UMR 6302, CNRS, Université de Bourgogne, 9 avenue Alain Savary, BP 47870, 21078, Dijon, Cedex, France; University of Applied Sciences Western Switzerland HES-SO, Haute Ecole d'Ingénierie et d'Architecture, Pérolles 80, 1700, Fribourg, Switzerland
| | - Demetrio Milea
- Università degli Studi di Messina, Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, CHIBIOFARAM, V.le F. Stagno d'Alcontres, 31, 98166, Messina, Italy
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Caffeic Acid/Eu(III) Complexes: Solution Equilibrium Studies, Structure Characterization and Biological Activity. Int J Mol Sci 2022; 23:ijms23020888. [PMID: 35055074 PMCID: PMC8775996 DOI: 10.3390/ijms23020888] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 01/09/2022] [Accepted: 01/11/2022] [Indexed: 12/15/2022] Open
Abstract
Caffeic acid (CFA) is one of the various natural antioxidants and chemoprotective agents occurring in the human diet. In addition, its metal complexes play fundamental roles in biological systems. Nevertheless, research on the properties of CFA with lanthanide metals is very scarce, and little to no chemical or biological information is known about these particular systems. Most of their properties, including their biological activity and environmental impact, strictly depend on their structure, stability, and solution behaviour. In this work, a multi-analytical-technique approach was used to study these relationships for the Eu(III)/CFA complex. The synthesized metal complex was studied by FT-IR, FT-Raman, elemental, and thermal (TGA) analysis. In order to examine the chemical speciation of the Eu(III)/CFA system in an aqueous solution, several independent potentiometric and spectrophotometric UV-Vis titrations were performed at different M:L (metal:ligand) and pH ratios. The general molecular formula of the synthesized metal complex in the solid state was [Eu(CFA)3(H2O)3]∙2H2O (M:L ratio 1:3), while in aqueous solution the 1:1 species were observed at the optimum pH of 6 ≤ pH ≤ 10, ([Eu(CFA)] and [Eu(CFA)(OH)]−). These results were confirmed by 1H-NMR experiments and electrospray-ionization mass spectrometry (ESI-MS). To evaluate the interaction of Eu(III)/CFA and CFA alone with cell membranes, electrophoretic mobility assays were used. Various antioxidant tests have shown that Eu(III)/CFA exhibits lower antioxidant activity than the free CFA ligand. In addition, the antimicrobial properties of Eu(III)/CFA and CFA against Escherichia coli, Bacillus subtilis and Candida albicans were investigated by evaluation of the minimum inhibitory concentration (MIC). Eu(III)/CFA shows higher antibacterial activity against bacteria compared to CFA, which can be explained by the highly probable increased lipophilicity of the Eu(III) complex.
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Crea F, De Stefano C, Milea D, Sammartano S. Phytate–molybdate( vi) interactions in NaCl (aq)at different ionic strengths: unusual behaviour of the protonated species. NEW J CHEM 2018. [DOI: 10.1039/c7nj04651k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Stepwise stability constants of phytate/molybdate(vi) complexes regularly increase with the number of protons in the species, affecting their speciation and sequestration.
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Affiliation(s)
- Francesco Crea
- Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, Università di Messina
- 31-98166 Messina
- Italy
| | - Concetta De Stefano
- Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, Università di Messina
- 31-98166 Messina
- Italy
| | - Demetrio Milea
- Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, Università di Messina
- 31-98166 Messina
- Italy
| | - Silvio Sammartano
- Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, Università di Messina
- 31-98166 Messina
- Italy
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Cardiano P, Cigala RM, Cordaro M, De Stefano C, Milea D, Sammartano S. On the complexation of metal cations with “pure” diethylenetriamine-N,N,N′,N′′,N′′-pentakis(methylenephosphonic) acid. NEW J CHEM 2017. [DOI: 10.1039/c7nj00118e] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Complexation of various metal cations by DTPMA obtained by an efficient synthetic procedure has been investigated, assessing its sequestering ability and speciation in real systems.
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Affiliation(s)
- Paola Cardiano
- Dipartimento di Scienze Chimiche
- Biologiche
- Farmaceutiche ed Ambientali
- Università di Messina
- 98166 Messina
| | - Rosalia Maria Cigala
- Dipartimento di Scienze Chimiche
- Biologiche
- Farmaceutiche ed Ambientali
- Università di Messina
- 98166 Messina
| | - Massimiliano Cordaro
- Dipartimento di Scienze Chimiche
- Biologiche
- Farmaceutiche ed Ambientali
- Università di Messina
- 98166 Messina
| | - Concetta De Stefano
- Dipartimento di Scienze Chimiche
- Biologiche
- Farmaceutiche ed Ambientali
- Università di Messina
- 98166 Messina
| | - Demetrio Milea
- Dipartimento di Scienze Chimiche
- Biologiche
- Farmaceutiche ed Ambientali
- Università di Messina
- 98166 Messina
| | - Silvio Sammartano
- Dipartimento di Scienze Chimiche
- Biologiche
- Farmaceutiche ed Ambientali
- Università di Messina
- 98166 Messina
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Bretti C, Cigala RM, Lando G, Milea D, Sammartano S. Sequestering ability of phytate toward biologically and environmentally relevant trivalent metal cations. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2012; 60:8075-8082. [PMID: 22845864 DOI: 10.1021/jf302007v] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Quantitative parameters for the interactions between phytate (Phy) and Al(3+), Fe(3+), and Cr(3+) were determined potentiometrically in NaNO(3) aqueous solutions at I = 0.10 mol L(-1) and T = 298.15 K. Different complex species were found in a wide pH range. The various species are partially protonated, depending on the pH in which they are formed, and are indicated with the general formula MH(q)Phy (with 0 ≤ q ≤ 6). In all cases, the stability of the FeH(q)Phy species is several log K units higher than that of the analogous AlH(q)Phy and CrH(q)Phy species. For example, for the MH(2)Phy species, the stability trend is log K(2) = 15.81, 20.61, and 16.70 for Al(3+), Fe(3+), and Cr(3+), respectively. The sequestering ability of phytate toward the considered metal cations was evaluated by calculating the pL(0.5) values (i.e., the total ligand concentration necessary to bind 50% of the cation present in trace in solution) at different pH values. In general, phytate results in a quite good sequestering agent toward all three cations in the whole investigated pH range, but the order of pL(0.5) depends on it. For example, at pH 5.0 it is pL(0.5) = 5.33, 5.44, and 5.75 for Fe(3+), Cr(3+), and Al(3+), respectively (Fe(3+) < Cr(3+) < Al(3+)); at pH 7.4 it is pL(0.5) = 9.94, 9.23, and 8.71 (Al(3+) < Cr(3+) < Fe(3+)), whereas at pH 9.0 it is pL(0.5) = 10.42, 10.87, and 8.34 (Al(3+) < Fe(3+) < Cr(3+)). All of the pL(0.5) values, and therefore the sequestering ability, regularly increase with increasing pH, and the dependence of pL(0.5) on pH was modeled using some empirical equations.
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Affiliation(s)
- Clemente Bretti
- Dipartimento di Chimica Inorganica, Chimica Analitica e Chimica Fisica, Università di Messina, Viale Ferdinando Stagno d'Alcontres 31, I-98166 Messina (Vill. S. Agata), Italy
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