A model describing the operation of the vapor pressure osmometer has been developed to account for the solute dependence of the calibration constant. This model envisions the existence of a diffusion-controlled surface concentration that differs from the concentration of the drop as a whole. Three limiting cases approximated for the surface concentration depend on the relative magnitudes of thermistor self-heating and solution concentration. Quantitative predictions of the dependence of d(ΔR)/d(V2) (the variation of thermistor resistance difference with thermistor self-heating) on both solute molecular weight and solution concentration are in good agreement with experimental data.
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B. H. Bersted (1974) studied this question.