A method is presented for fast and accurate determination of the limiting activity coefficient of a solute dissolved in a liquid mixture. It is based on the study of the solute elution with time; the solute is stripped from the solution by a constant flow of inert gas. The variation of solute concentration in the gaseous phase is measured by gasliquid chromatography. Experimental results for several systems are in good agreement with data from retention time measurements and extrapolation of vapor-liquid equilibria.