RELATIVE MEASUREMENTS OF ACTIVITY-COEFFICIENTS AT INFINITE DILUTION BY GAS-CHROMATOGRAPHY

In this paper, a relative measurement technique for infinite dilution activity coefficients by gas-liquid chromatography (GLC) is introduced. The method makes use of an internal standard whose infinite dilution activity coefficient in the solvent loaded on the column is known, and allows simultaneous, rapid, and accurate measurements of infinite dilution activity coefficients. The technique is particularly suitable for evaluation of activity coefficients of solutes in volatile solvents; such systems are difficult to investigate by the conventional GLC method due to solvent stripping. Some experimental results obtained by the method proposed here are presented and compared with those obtained earlier by other methods. As part of this work, the governing equations for the GLC technique taking into account the volatility of the solvent were developed.