Correlation and Prediction of Osmotic Pressures for Aqueous Bovine Serum Albumin–NaCl Solutions Based on Two Yukawa Potentials

Abstract

A new equation of state is proposed to correlate and predict the osmotic pressure data for aqueous bovine serum albumin (BSA) solutions with different NaCl concentrations and pH values with only one adjustable parameter. The Carnahan–Starling equation represents the contribution of the hard sphere repulsion to the osmotic pressure. The attractive dispersion and double-layer repulsion interactions are represented by two Yukawa potentials, respectively. The equation of state of Duh and Mier-Y-Teran for one Yukawa potential is expanded to two Yukawa potentials to describe the nonidealities of the charged BSA–aqueous NaCl solution, instead of the classical DLVO theory. The average relative deviation of correlation of the osmotic pressure in 0.15 M NaCl solution is 18%. The average relative deviation of prediction in 1–5 M NaCl solutions is 20.33%. A comparison with other models and the limitations of our model are discussed.