The technique involves choice of a mathematical model for describing the sorption dynamics, calculation of the thermodynamic and kinetic properties of ion sorption in a given system, and plotting of sorption isotherms of a microcomponent in a wide range of concentrations of interfering macrocomponents. The technique has been used for studying the sorption of nitrate in the presence of bicarbonate and sulfate ions. It has been shown that the nitrate sorption dynamics is adequately described by the external diffusion model. The data obtained have been used for predicting the recovery levels of nitrate as a function of the sample volume containing sulfate. The accuracy of the prediction has been proved experimentally.