Modeling S-carboxymethyl-l-cysteine protonation and activity coefficients in sodium and tetramethylammonium chloride aqueous solutions by SIT and Pitzer equations

Bretti, Clemente; Giacalone, Alba; Gianguzza, Antonio; Milea, Demetrio; Sammartano, Silvio

doi:10.1016/j.fluid.2006.12.006

Cited by 28 publications

(34 citation statements)

References 18 publications

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“…According to previous papers (Bretti et al 2007(Bretti et al , 2008, k m and k c were expressed here as…”

Section: Calculationsmentioning

confidence: 99%

“…The dependence on medium and ionic strength of the protonation and complex formation constants of glutathione was taken into account by an EDH type equation and by the SIT (Biederman 1975(Biederman , 1986; Grenthe and Puigdomenech 1997) model: Both C i and De i are generally true constants, but several studies (e.g., Bretti et al 2006Bretti et al , 2007Bretti et al , 2008Crea et al 2007;De Stefano et al 2006;Cigala et al 2010) demonstrated that they may be better expressed as a function of the ionic strength:…”

Section: Calculationsmentioning

confidence: 99%

“…An extensive discussion on the applications of both the EDH and SIT models to protonation data and activity coefficients may be found, e.g., in (De Stefano et al 2006;Bretti et al 2007;Crea et al 2007) and references therein. Below, the expressions of De i coefficients are reported, just as an example, for glutathione protonation constants (Eq.…”

Section: Calculationsmentioning

confidence: 99%

“…Pitzer equations were also used to model the dependence of the stability constants of glutathione species on ionic strength, both in their simplified and classical forms (the historical aspects and the theoretical basis one may refer, for example, to Pitzer (1973Pitzer ( , 1991 and Millero (1982Millero ( , 2001, while references (De Stefano et al 2006;Bretti et al 2007;Crea et al 2007) may be useful for their application to protonation data). The most directly applicable and widely used forms for the expression of activity coefficients of single ions, for a cation M z?…”

Section: Calculationsmentioning

confidence: 99%

“…Here it is interesting to pay attention on some other aspects. Several studies (e.g., (Foti et al 1997;Bretti et al 2007)) demonstrated that, at least for the simplest systems, different models for the dependence of various thermodynamic parameters DH ij 0 refer to equilibrium: jCa 2? ?…”

Section: Final Considerationsmentioning

confidence: 99%

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Modeling the acid–base properties of glutathione in different ionic media, with particular reference to natural waters and biological fluids

et al. 2011

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The acid-base properties of γ-L-glutamyl-L-cysteinyl-glycine (glutathione, GSH) were determined by potentiometry (ISE-H(+), glass electrode) in pure NaI((aq)) and in NaCl((aq))/MgCl(2(aq)), and NaCl((aq))/CaCl(2(aq)) mixtures, at T = 298.15 K and different ionic strengths (up to I(c) ~ 5.0 mol L(-1)). In addition, the activity coefficients of glutathione were also determined by the distribution method at the same temperature in various ionic media (LiCl((aq)), NaCl((aq)), KCl((aq)), CsCl((aq)), MgCl(2(aq)), CaCl(2(aq)), NaI((aq))). The results obtained were also used to calculate the Specific ion Interaction Theory (SIT) and Pitzer coefficients for the dependence on medium and ionic strength of glutathione species, as well as the formation constants of weak Mg(j)H( i )(GSH)((i+2j-3)) and Ca(j)H(i)(GSH)((i+2j-3)) complexes. Direct calorimetric titrations were also carried out in pure NaCl((aq)) and in NaCl((aq))/CaCl(2(aq)) mixtures at different ionic strengths (0.25 ≤ I (c )/mol L(-1) ≤ 5.0) in order to determine the enthalpy changes for the protonation and complex formation equilibria in these media at T = 298.15 K. Results obtained are useful for the definition of glutathione speciation in any aqueous media containing the main cations of natural waters and biological fluids, such as Na(+), K(+), Mg(2+), and Ca(2+). Finally, this kind of systematic studies, where a series of ionic media (e.g., all alkali metal chlorides) is taken into account in the determination of various thermodynamic parameters, is useful for the definition of some trends in the thermodynamic behavior of glutathione in aqueous solution.

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“…According to previous papers (Bretti et al 2007(Bretti et al , 2008, k m and k c were expressed here as…”

Section: Calculationsmentioning

confidence: 99%

Section: Calculationsmentioning

confidence: 99%

Section: Calculationsmentioning

confidence: 99%

Section: Calculationsmentioning

confidence: 99%

Section: Final Considerationsmentioning

confidence: 99%

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Modeling the acid–base properties of glutathione in different ionic media, with particular reference to natural waters and biological fluids

et al. 2011

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Alkali Metal Ion Complexes with Phosphates, Nucleotides, Amino Acids, and Related Ligands of Biological Relevance. Their Properties in Solution

Crea

Stefano

Foti

et al. 2016

Metal Ions in Life Sciences

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Alkali metal ions play very important roles in all biological systems, some of them are essential for life. Their concentration depends on several physiological factors and is very variable. For example, sodium concentrations in human fluids vary from quite low (e.g., 8.2 mmol dm(-3) in mature maternal milk) to high values (0.14 mol dm(-3) in blood plasma). While many data on the concentration of Na(+) and K(+) in various fluids are available, the information on other alkali metal cations is scarce. Since many vital functions depend on the network of interactions occurring in various biofluids, this chapter reviews their complex formation with phosphates, nucleotides, amino acids, and related ligands of biological relevance. Literature data on this topic are quite rare if compared to other cations. Generally, the stability of alkali metal ion complexes of organic and inorganic ligands is rather low (usually log K < 2) and depends on the charge of the ligand, owing to the ionic nature of the interactions. At the same time, the size of the cation is an important factor that influences the stability: very often, but not always (e.g., for sulfate), it follows the trend Li(+) > Na(+) > K(+) > Rb(+) > Cs(+). For example, for citrate it is: log K ML = 0.88, 0.80, 0.48, 0.38, and 0.13 at 25 °C and infinite dilution. Some considerations are made on the main aspects related to the difficulties in the determination of weak complexes. The importance of the alkali metal ion complexes was also studied in the light of modelling natural fluids and in the use of these cations as probes for different processes. Some empirical relationships are proposed for the dependence of the stability constants of Na(+) complexes on the ligand charge, as well as for correlations among log K values of NaL, KL or LiL species (L = generic ligand).

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Speciation of Phytate Ion in Aqueous Solution. Thermodynamic Parameters for Zinc(II) Sequestration at Different Ionic Strengths and Temperatures

et al. 2008

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Modeling S-carboxymethyl-l-cysteine protonation and activity coefficients in sodium and tetramethylammonium chloride aqueous solutions by SIT and Pitzer equations

Cited by 28 publications

References 18 publications

Modeling the acid–base properties of glutathione in different ionic media, with particular reference to natural waters and biological fluids

Modeling the acid–base properties of glutathione in different ionic media, with particular reference to natural waters and biological fluids

Alkali Metal Ion Complexes with Phosphates, Nucleotides, Amino Acids, and Related Ligands of Biological Relevance. Their Properties in Solution

Speciation of Phytate Ion in Aqueous Solution. Thermodynamic Parameters for Zinc(II) Sequestration at Different Ionic Strengths and Temperatures

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