Interactions in (l-phenylalanine/l-histidine + 0.01 mol · kg−1 aqueous β-cyclodextrin) systems at T = (293.15, 298.15, 303.15 and 308.15) K

Densities (ρ) and speeds of sound (u) have been measured for (l-phenylalanine + 0.01 mol · kg−1 aqueous β-cyclodextrin) and (l-histidine + 0.01 mol · kg−1 aqueous β-cyclodextrin) systems at T = (293.15, 298.15, 303.15 and 308.15) K using the density and sound velocity Meter DSA 5000 M. The ρ and u   values have been utilized to evaluate values of the partial molar volume (ϕv∘), transfer partial molar volume (Δtrϕv∘), partial molar isentropic compressibility (ϕk∘), and transfer partial molar isentropic compressibility (Δtrϕk∘) of the systems studied. The experimentally measured and calculated parameters have been interpreted in terms of host-guest and ion-hydrophilic interactions operative in the systems.

► The host-guest and ion-hydrophilic interactions operate in systems.
► The larger ϕv∘ of l-phenylalanine is due to its phenyl ring.
► The ϕk∘ of l-histidine is higher than l-phenylalanine.
► The ϕk∘ of l-phenylalanine and l-histidine increase with temperature.