Use of ion-selective electrodes in the evaluation of stability constants of sparingly soluble salts. Application to the lead(II)-fluoride system in aqueous solution

The purpose of our work was to examine the metal binding abilities of selected peptide bound Maillard reaction products (MRPs). The Nα-hippuryl-protected MRPs Nε-fructoselysine and Nε-carboxymethyllysine were synthesised and measurement of stability constants for complexes formed with the physiologically important metal ions copper(II) and zinc(II) was carried out in aqueous solution (T = 298.1 K; I = 0.1M KNO3) using pH-potentiometry. The stability constants of Nε-fructoselysine and Nε-carboxymethyllysine with Cu(II) proved that new coordination centres are formed by the nonenzymatic glycation of proteins. With zinc(II) no complexation was observed. Physiological consequences are discussed, but further studies are necessary in order to clarify the effects of this phenomenon.

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Stability constants for some transition metal complexes of adenosine and 9-(β-D-ribofuranosyl)purine in aqueous solution

Inorganica Chimica Acta ◽

10.1016/s0020-1693(00)90779-5 ◽

1981 ◽

Vol 55 ◽

pp. 39-42 ◽

Cited By ~ 21

Author(s):

Harri Lönnberg ◽

Jorma Arpalahti

Keyword(s):

Aqueous Solution ◽

Transition Metal ◽

Metal Complexes ◽

Stability Constants ◽

Transition Metal Complexes

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Polarographic Study of the Complexation of Na+ and K+ Ions by Dibenzo-18-crown-6 in Non-Aqueous Solution

Australian Journal of Chemistry ◽

10.1071/ch9902003 ◽

1990 ◽

Vol 43 (12) ◽

pp. 2003 ◽

Cited By ~ 3

Author(s):

E Lada ◽

A Urbanczyk ◽

MK Kalinowski

Keyword(s):

Aqueous Solution ◽

Stability Constants ◽

Polarographic Study

Complexes of Na+ and K+ ions with dibenzo-18-crown-6 (6,7,9,10,17,18,20,21-octahydro-dibenzo[ b,k ] [1,4,7,10,13,16] hexaoxacyclooctadecin ) were studied by polarography in several non-proton-donating media. Their stability constants are strongly influenced by the solvents, and vary inversely with the Gutmann donicity scale and with the Persson HDS parameter which is a measure of the hardness for these solvents.

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Interaction of Ampicillin and Amoxicillin with Mn2+: A Speciation Study in Aqueous Solution

Molecules ◽

10.3390/molecules25143110 ◽

2020 ◽

Vol 25 (14) ◽

pp. 3110

Author(s):

Claudia Foti ◽

Ottavia Giuffrè

Keyword(s):

Aqueous Solution ◽

Stability Constants ◽

Metal Ion ◽

Formation Constants ◽

Enthalpy Change ◽

Ligand Concentration ◽

Empirical Parameter ◽

Speciation Study ◽

Potentiometric Measurements ◽

The Stability

A potentiometric and UV spectrophotometric investigation on Mn2+-ampicillin and Mn2+-amoxicillin systems in NaCl aqueous solution is reported. The potentiometric measurements were carried out under different conditions of temperature (15 ≤ t/°C ≤ 37). The obtained speciation pattern includes two species for both the investigated systems. More in detail, for system containing ampicillin MLH and ML species, for that containing amoxicillin, MLH2 and MLH ones. The spectrophotometric findings have fully confirmed the results obtained by potentiometry for both the systems, in terms of speciation models as well as the stability constants of the formed species. Enthalpy change values were calculated via the dependence of formation constants of the species on temperature. The sequestering ability of ampicillin and amoxicillin towards Mn2+ was also evaluated under different conditions of pH and temperature via pL0.5 empirical parameter (i.e., cologarithm of the ligand concentration required to sequester 50% of the metal ion present in traces).

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