RETENTION AND COLUMN EFFICIENCY SIMULATIONS IN PROGRAMMED-TEMPERATURE GAS-CHROMATOGRAPHY - THEORY AND APPLICATION

A model including the effect of the temperature dependence of carrier gas viscosity, and using as input two thermodynamic parameters Delta ($) over bar H(0)v and A (entropy term), leads to retention temperatures. These thermodynamical values differ, either referring solutes to methane or using a mathematical dead time, but lead to calculated retention temperatures comparable in the whole with measured ones. Subsequently, programmed retention times and retention indices, calculated by both linear and polynomial interpolations, are deduced. Predicted retention correlate with observed data, with a P-value less than or equal to 0.01. Retention indices calculated by linear and polynomial interpolations for the components of a test-mixture are different. The polynomial technique furnishes results that are more consistent with the scheme of retention indices, and have smaller standard-deviations. If the dependence of HETP on temperature is specified in isothermal elution, it is possible to predict the HETP for programmed temperature elution and subsequently width at half-height. Predicted and measured peak widths corresponded within 5-9%.