The diffusion coefficients of some amino acids in the aqueous solutions at 30℃ were determined by the metallic diaphragm cell method which is characterized by accuracy

promptness and convenience. The cell constant was determined by measuring the diffusion coefficient of KCl aqueous solutions at 25℃. The reliability of the experimental method was verified by the system of sucrose-water at 25℃ with known diffusion coefficient. Based on the integral diffusion coefficients

the relationships among differential diffusion coefficients

densities

viscosities and concentration were correlated. A semi-empirical model which had been proposed and verified by some known system was extended to correlate the diffusion coefficients of amino acids in the aqueous solutions.The fitting accuracy of this model is satisfactory.