Conductivity properties of hyaluronate salts in simple salt-free and sample salt-containing solutions

Abstract

Electrical conductivities of sodium and calcium hyaluronate were measured in aqueous solution at 25°C. Measurements were also made on sodium hyaluronate in aqueous NaCl in simple salt concentrations of 0.01 and 0.001 mol dm −3. For simple salt-free solutions, the agreement between experimental equivalent conductivity of the polyelectrolyte and the theoretical values according to the Manning theory are satisfactory although relatively insensitive to the value of the linear charge density parameter, for both counterion forms. For sodium hyaluronate in aqueous sodium chloride solutions, the values of the theoretical equivalent conductivities for sodium hyaluronate were calculated for two values of the linear charge parameter, 0.6 and 0.7. Both linear charge parameter values gave reasonable correspondence to the experimental values but, at both concentrations of added sodium chloride, the value of 0.6 for the linear charge parameter of sodium hyaluronate gave closer correspondence. The theoretical dependence of equivalent conductivity on salt concentration is discussed.