Abstract
A modified procedure for analysing concentration profiles from diffusion experiments is described. It is based on the Boltzmann-Matano method but the concentration profile is transformed to give a linear function in the special case of concentration-independent diffusion. The transformed profile is fitted with a least-squares cubic spline to facilitate the subsequent calculations. Some difficulties associated with the more conventional polynomial fitting of the concentration profile are overcome or reduced. The procedure allows data smoothing in accordance with realistic experimental errors. Results of tests of both methods are presented and the modified procedure appears to be generally sounder.