LAUSR

Abstract Densities, conductivities, UV absorption and fluorescence spectral measurements for mixed aqueous solutions of amino acid/glycyl dipeptide (glycine, l -alanine, l -valine, l -leucine, glycylglycine, glycyl- l -valine, glycyl- l -leucine) and benzalkonium chloride (BC) were done at various temperatures T = (293.15, 298.15, 303.15, 308.15 and 313.15) K. Various parameters like standard partial molar volume, V2, φ0, standard partial molar transfer volume, ΔtV0, partial molar expansibility, Eφ0 and hydration number, nH of amino acid/glycyl dipeptide, aggregation number, Nagg, critical micellar concentration, cmc, hydrodynamic radius, Rh, packing parameter, P and thermodynamic parameters for micellization of BC, the binding constant between small biomolecules and BC have been calculated. Also, the contributions to V2, φ0 from (NH3+, COO−), CH2 and (CH2CONH) groups were evaluated. The results were analyzed based on physicochemical interactions in the considered ternary systems. Effect of hydrocarbon side chain length of amino acids/dipeptides, temperature, and concentration on the obtained parameters clearly suggests the physicochemical behaviour of small biomolecules and benzalkonium chloride in solute–solvent interactions.