Rey-Castro, CarlosHerrero, RobertoSastre de Vicente, Manuel2005-11-032005-11-032004Journal of electroanalytical chemistry, 2004, vol. 564, p. 223-2301572-6657http://hdl.handle.net/2183/173[Abstract] The apparent proton dissociation constants of a commercial alginic acid have been obtained in KNO3 and NaCl at concentrations ranging between 0.01 and 2 mol·L-1. An analysis of the dependence on the ionic strength at a constant value of the dissociation degree was done by means of empirical functions derived from the Gibbs-Donnan formalism for polyelectrolytes and a specific ion interaction theory (SIT). Both functions were able to fit the experimental data, although SIT yielded rather high errors in the fitted parameters due to a problem of multicollinearity, in contrast to the function derived from the Gibbs-Donnan approach.application/pdfengPotentiometryGibbs-Donnan modelSpecific ion interaction theoryAlginic acidEquilibrium constantsjournal articleopen access