Elution parameters in constant-pressure, single-ramp temperature-programmed gas chromatography

The dependence of the degree of interaction of a solute with the stationary phase at the time of its elution from the column in temperature-programmed GC is best described by interaction level of the solute. The latter represents the fraction of a solute residing in the stationary phase relative to the total amount of the solute. A simple approach to the evaluation of interaction levels of eluting solutes in a single-ramp temperature program is proposed. In a single-ramp temperature program having no preceding temperature plateau, all solutes that elute at temperatures that are about 60°C higher than the initial temperature of the heating ramp elute with nearly the same interaction levels that can be found as exp(− r), where r is dimensionless heating rate. A specially designed temperature plateau preceding the ramp causes all solutes eluting during the entire time of the ramp to elute with nearly the same interaction levels equal to exp(− r). A transformation of the interaction level of a solute into its retention factor or mobility factor (a fraction of a solute in a mobile phase in relation to the total amount of the solute) and vice versa is also described.