A non-linear least-squares approach to the refinement of all parameters involved in acid—base titrations.

Arena, Giuseppe; Rizzarelli, Enrico; Sammartano, Silvio; Rigano, Carmelo

doi:10.1016/0039-9140(79)80146-0

Cited by 127 publications

(49 citation statements)

References 40 publications

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“…The ACBA-program developed by Arena et al (23), for example, is particularly useful for the potentiometric examination of acids and bases (weak and strong). This program calculates the "best" acidlbase formation constants and concentrations from glass-electrode emf-readings and added titrant volumes.…”

Section: Theorymentioning

confidence: 99%

Formation constants for selected organo—metal (Al³⁺, Fe³⁺)—phosphate complexes

Arp¹,

Meyer²

1985

Can. J. Chem.

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. Can. J. Chem. 63, 3357 ( 1985). The possible formation of organo-metal-phosphate complexes (0-M-P) in aqueous solutions is examined by potentiometric titration analysis. The complex-forming solutions contain A?+-ions or Few-ions, organic acids (salicylic, phthalic, oxalic, and citric acids) and phosphate ions. The titrations are done within the precipitation-free pH-region from 2 to 4.5 (approximately) at 25°C under nitrogen at an ionic strength of 0.2 M KC1. ' The calibration of the electrode pair (glass-electrode, calomel-reference electrode) and the determination of the formation constants are facilitated by analyzing the pertinent curves with the ACBA-(Arena et 01.) and MINIQUAD-(Cans et 01.) computer programs. The results suggest (i) that 0-M-P complexes are readily formed, and that the power of selected organic acids to form ternary mixed-ligand complexes with A1"-ions and phosphate ions decreases in the order salycilate > citrate > oxalate > phthalate. Also, Fe"-ions are found to be more strongly bound by salicylate and phosphate ions than ~l'+-ions. The effect of 0-M-P formation on the chemical speciation of Al in buffered aqueous solutions containing mineral nutrients for the growth of biological organisms is demonstrated for a special case study. Dans une etude d'un cas spCcial, on a pu demontrer I'influence de la formation du complexe 0-M-P sur la speciation chimique de I'aluminium dans des solutions aqueuses tamponees contenant des sels mintraux facilitant la croissance d'organismes biologiques.[Traduit par le journal]

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Section: Theorymentioning

confidence: 99%

Formation constants for selected organo—metal (Al³⁺, Fe³⁺)—phosphate complexes

Arp¹,

Meyer²

1985

Can. J. Chem.

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“…One means of overcoming this limitation to the use of pH titrations is to reduce the effective MeHg(1I) thiolate constant by competition with another li-'During this work the programs ACBA (27) and MUPROT (28) were reported. These serve the same purpose as TITRAT, but do not use the statistically rigorous weighting scheme necessary for titrations in which titrant volumes and pH have comparable uncertainties (26).…”

Section: Calrulotiorz Of Eqrtilibriurn Constarltsmentioning

confidence: 99%

Methylmercury(II) sulfhydryl interactions. Potentiometric determination of the formation constants for complexation of methylmercury(II) by sulfhydryl containing amino acids and related molecules, including glutathione

Arnold¹,

Canty²

1983

Can. J. Chem.

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Formation constants for the interaction of methylmercury(II) with 2-mercaptoethanol, mercaptoacetic acid, O-methyl-mercaptoacetate, 2-mercaptosuccinic acid, L-cysteine, D,L-penicillamine, N-acetyl-D,L-penicillamine, glutathione, thiocholine, and 4-mercapto-N-methylpiperidine have been determined by potentiometric titration. For the equilibrium [Formula: see text], log β occurs in the range 14.60(1)–17.14(1), with the lowest value obtained for the cationic complex of thiocholine, [Formula: see text]. Acid dissociation constants for the ligands are reported. Formation constants for the addition of both one and two equivalents of MeHg(II) to L-cysteine have been determined, giving log K ca. 4.1 for the reaction[Formula: see text]occurring at low pH, and log K 8.8 for the reaction[Formula: see text]occurring at higher pH.

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“…l. The acidity constants involved in this titration have been determined by using the ACBA program (ARENA et al, 1978). Values of p*K~1 = 4.40 ± 0.23 and p* K~= 6.45 ± 0.25 were obtained as a result of different titrations of chitin in 0.7 M NaC!.…”

Section: {Rh}mentioning

confidence: 99%

“…Since chitin is a EXPERIMENTAL where E* is the apparent emfin the medium; and R, T, and Fhave their usual meanings. The values for E*, the stoichiometric ionization constants K~i' and the cation exchange capacity were determined from the titrations using a non-linear least-squares program (ARENA et al, 1978). A typical titration of chitin is shown in Fig.…”

Section: Introducnonmentioning

confidence: 99%

The adsorption of copper to chitin in seawater

González‐Dávila

Millero

1990

Geochimica et Cosmochimica Acta

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Abstract-The interaction of metal ions with particulate matter is important in Iimiting their concentration in seawater. Chitin is one of the constituents of the natural particulate organic matter than can interact with metal ions and therefore may serve as a reasonable model for natural organic solids. The adsorption of Cu 2+ on the chitin surface has been studied in seawater as a function of pH, temperature, and salinity. The amphoteric properties of the surface of chitin were characterized in 0.7 M NaCl in terms of a twoprotic acid-base system (pHpzc = 5.4) with acidity constants p*K~1 = 4.4 ± 0.2 and p* K~2 = 6.4 ± 0,2. The maxim.um proton exchange capacity ofchitin was found to be 2.3 ± 0.3 mol kg-I , broadly similar to other sohds. The rates ofthe adsorption were quite rapid (t1/2 = 8 min) and not strongly affected by the presence of other metals such as Cd 2 + and Pb 2 +. The adsorption equilibrium data have been found to correlate~ell with.~u~ace complex-formation equilibria or the mathematically equivalent Langmuirtype adsorptlOn eqUlhbna. The value for the stability constant of Cu 2+ on chitin was found to be 10g*K'':I = 8.?5 ± 0.01, and the~omplexing capacity ofchitin was found to be 6.9 and 5.9 J.Lmol g-I, respectIv~ly, ID the absence and l~the presence of Cd2+ and Pb2+. An increase in the salinity and a decrease ID the temperature result ID greater adsorption of Cu 2+ to chitin. INTRODUcnON

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A non-linear least-squares approach to the refinement of all parameters involved in acid—base titrations.

Cited by 127 publications

References 40 publications

Formation constants for selected organo—metal (Al³⁺, Fe³⁺)—phosphate complexes

Formation constants for selected organo—metal (Al³⁺, Fe³⁺)—phosphate complexes

Methylmercury(II) sulfhydryl interactions. Potentiometric determination of the formation constants for complexation of methylmercury(II) by sulfhydryl containing amino acids and related molecules, including glutathione

The adsorption of copper to chitin in seawater

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A non-linear least-squares approach to the refinement of all parameters involved in acid—base titrations.

Cited by 127 publications

References 40 publications

Formation constants for selected organo—metal (Al3+, Fe3+)—phosphate complexes

Formation constants for selected organo—metal (Al3+, Fe3+)—phosphate complexes

Methylmercury(II) sulfhydryl interactions. Potentiometric determination of the formation constants for complexation of methylmercury(II) by sulfhydryl containing amino acids and related molecules, including glutathione

The adsorption of copper to chitin in seawater

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Formation constants for selected organo—metal (Al³⁺, Fe³⁺)—phosphate complexes

Formation constants for selected organo—metal (Al³⁺, Fe³⁺)—phosphate complexes