Effect of the Alkali-Metal Cations On the Protonation Constants of Myo-Inositol Hexakis(Phosphate)

Bieth, H.; Jost, Pierre; Spiess, Bernard; Wehrer, C.

doi:10.1080/00032718908051358

Cited by 18 publications

(15 citation statements)

References 23 publications

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“…Bebot-Brigaud [20] and Sala [21] reported studies at T = 293.15 K, Torres et al [22] at T = 310.15 K, De Carli et al [76] at T = 309.15 K and Costello [18] at 301.15 K. Some authors (Bieth [17,75] and Bebot-Brigaud [20]) used (C 2 H 5 ) 4 NClO 4 as background salt, or (C 3 H 7 ) 4 NBr (Costello [18]). Other values are reported in pure water, as in Barrè [77] and Brigando [19], Hoff-Jorgensen [78], Evans [79], De Stefano et al [23].…”

Section: Literature Comparisonmentioning

confidence: 95%

“…Some authors reported the protonation constants for all the twelve steps, whereas many others have determined less species, often no more than eight. According to Bieth et al [17,75] the phytate protonated species are formed in a very acidic or very basic pH range, therefore the determination of their stability is often not very accurate, also because of the presence of more than one species at the same pH value.…”

Section: Literature Comparisonmentioning

confidence: 99%

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The effect of the tetraalkylammonium salts on the protonation thermodynamics of the phytate anion

Bretti

Cigala

Stefano

et al. 2014

Fluid Phase Equilibria

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Section: Literature Comparisonmentioning

confidence: 95%

Section: Literature Comparisonmentioning

confidence: 99%

The effect of the tetraalkylammonium salts on the protonation thermodynamics of the phytate anion

Bretti

Cigala

Stefano

et al. 2014

Fluid Phase Equilibria

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“…Moreover, most of the measurements are performed only in a single ionic medium and at a single ionic strength. Indeed our bibliographical research turned up only two papers reporting data at different ionic strengths (but no explanation of effect on phytate protonation was offered) [17,19], and only in an article by Bieth et al [18] is there any attempt to explain the influence of the nature of the ionic medium (alkaline chlorides) on the acid-base properties of phytate. As these authors write in their paper, "the approach attempted in this work must be considered as qualitative.…”

Section: Comparisons With Literaturementioning

confidence: 99%

“…Despite this, few papers report quantitative data on its acid-base properties and interactions with alkali metal ions [3,13,14,15,16,17,18,19,20,21,22]. In order to obtain information on the speciation of phytate in natural aqueous media, one must study its protonation in different supporting electrolytes at different ionic strengths, and its complexes with the major cationic components of natural fluids, i.e., alkali and alkaline earth cations at different concentrations.…”

Section: Introductionmentioning

confidence: 98%

Speciation of phytate ion in aqueous solution. Alkali metal complex formation in different ionic media

et al. 2003

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The acid-base properties of phytic acid [ myo-inositol 1,2,3,4,5,6-hexakis(dihydrogen phosphate)] (H(12)Phy; Phy(12-)=phytate anion) were studied in aqueous solution by potentiometric measurements ([H+]-glass electrode) in lithium and potassium chloride aqueous media at different ionic strengths (0< I mol L(-1)< or =3) and at t=25 degrees C. The protonation of phytate proved strongly dependent on both ionic medium and ionic strength. The protonation constants obtained in alkali metal chlorides are considerably lower than the corresponding ones obtained in a previous paper in tetraethylammonium iodide (Et(4)NI; e.g., at I=0.5 mol L(-1), log K(3)(H)=11.7, 8.0, 9.1, and 9.1 in Et(4)NI, LiCl, NaCl and KCl, respectively; the protonation constants in Et(4)NI and NaCl were already reported), owing to the strong interactions occurring between the phytate and alkaline cations present in the background salt. We explained this in terms of complex formation between phytate and alkali metal ions. Experimental evidence allows us to consider the formation of 13 mixed proton-metal-ligand complexes, M(j)H(i)Phy((12-i-j)-), (M+ =Li+, Na+, K+), with j< or =7 and i< or =6, in the range 2.5< or =pH< or =10 (some measurements, at low ionic strength, were extended to pH=11). In particular, all the species formed are negatively charged: i+j-12=-5, -6. Very high formation percentages of M+-phytate species are observed in all the pH ranges investigated. The stability of alkali metal complexes follows the trend Li+ > or =Na+K+. Some measurements were also performed at constant ionic strength (I=0.5 mol L(-1)), using different mixtures of Et(4)NI and alkali metal chlorides, in order to confirm the formation of hypothesized and calculated metal-proton-ligand complex species and to obtain conditional protonation constants in these multi-component ionic media.

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“…However, relatively few studies have been reported in the literature concerning the acidbase properties of phytate as well as its complexing capacity towards metal ions [10,11,12,13,14,15,16,17,18,19,20]: this type of equilibrium reaction has been mainly investigated by combining potentiometry and spectrophotometry with NMR and/or calorimetric methods.…”

Section: Introductionmentioning

confidence: 99%

Complex formation between phytic acid and divalent metal ions: a solution equilibria and solid state investigation

Vasca

Materazzi

Caruso

et al. 2002

Analytical and Bioanalytical Chemistry

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An investigation on the complex formation equilibria between divalent metal ions Me (with Me=Mn, Co, Ni, Cu, Cd, and Pb) and phytic acid (H(12)L) is presented. Experiments were performed through a potentiometric methodology by measuring, at 25 degrees C, the proton and, in some cases (Cu(2+), Cd(2+), and Pb(2+)), also the metal ion activity at equilibrium in solutions containing, besides the metal and the ligand, 3 M NaClO(4) as the ionic medium. Unhydrolyzed solutions of the metal ion at millimolar concentration levels were titrated with solutions of about 10 mM sodium phytate, until the formation of a solid phase took place (always at pH approximately 2.5, except in the case of Cu(2+), which formed soluble complexes up to pH approximately 3.3). Coulometry was employed to produce very dilute solutions of either Cu(2+), Cd(2+), or Pb(2+) of accurately known composition. The emf data were explained by assuming, in the acidity interval explored, the formation of the complexes of general stoichiometry MeH(5)L(5-) and Me(2)H(3)L(5-). Coordination compounds in the solid state were also synthesized and characterized by elemental analysis, thermal analysis, and ICP spectroscopy. The solids had a general stoichiometry Me(6)H (t)LCl (t). x H(2)O, with the following t and x values for each metal investigated: Me ( t; x) = Mn (4; 2); Co (4; 2); Ni (4; 2); Cu (2; 2.5); Zn (2; 1); Sn (6; 6).

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Effect of the Alkali-Metal Cations On the Protonation Constants of Myo-Inositol Hexakis(Phosphate)

Cited by 18 publications

References 23 publications

The effect of the tetraalkylammonium salts on the protonation thermodynamics of the phytate anion

The effect of the tetraalkylammonium salts on the protonation thermodynamics of the phytate anion

Speciation of phytate ion in aqueous solution. Alkali metal complex formation in different ionic media

Complex formation between phytic acid and divalent metal ions: a solution equilibria and solid state investigation

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