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 repres ents 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 inte raction levels of eluting solutes in a single-ramp temperature program is p roposed. In a single-ramp temperature program having no preceding temperatu re plateau, all solutes that elute at temperatures that are about 60 degree sC higher than the initial temperature of the heating ramp elute with nearl y the same interaction levels that can be found as exp(-r), where v is dime nsionless heating rate. A specially designed temperature plateau preceding the ramp causes all solutes eluting during the entire time of the ramp to e lute with nearly the same interaction levels equal to exp(-r). A transforma tion of the interaction level of a solute into its retention factor or mobi lity factor (a fraction of a solute in a mobile phase in relation to the to tal amount of the solute) and vice versa is also described. (C) 2001 Eisevi er Science B.V. All rights reserved.