Elution and molecular weight parameters in exclusion chromatography

The mode of the chromatogram is inadequate for characterizing experimental elution curves, which are generally dissymmetrical. It is also dependent on axial diffusion. When the molecular weight distribution is defined either by the generalized exponential function or by the log-normal function, simulation of elution at finite resolution shows that the calibration curve at infinite resolution, independent of the flow rate of the carrier fluid, is approximated validly by correlating the first moment of the chromatogram (MEV) with the geometrical compound average ( M ̄n M ̄w) 1 2 = M0. The concentration effect seems to be controlled by a double extrapolation procedure defined by (1) treatment of the chromatograms using the calibration curve at zero concentration (InM0 versus lim c→o MEV), and (2) linear extrapolation to infinite dilution of the calculated molecular weight averages. © 1980.SCOPUS: ar.j