Theoretical and experimental analysis of the open-ended capillary diffusion method for study of the state of trace elements
in aqueous solutions is presented. It is shown by theoretical considerations that the use of the discontinuous capillary method
of diffusion and the evaluation of single measurements using the classical Anderson-Saddington equation yields incorrect diffusion
coefficients if two or more forms of the trace element with significantly different diffusion characteristics are simultaneously
present in the solution. A new method for the evaluation of diffusion is suggested, which enables calculation of the abundance
of two different forms of a trace element. The method employs a continuous measurement of diffusion combined with computer
analysis of the data obtained. Verification of the method is carried out for a particular case using trace radiocerium. The
effect of adsorption on the diffusion measurement and interpretation is discussed.