Chromatographic adhesion law to simplify surface energy calculation.

The calculated data of inverse gas chromatography (IGC) vary depending on the calculation methods and the n-alkane series. To overcome IGC data variability, this paper combines the Van Oss–Good–Chaudhury concept, the Dorris–Gray equation, the Schultz equation, the Fowkes equation and group contribution theory to establish the chromatographic adhesion law and its equation is K(a)(i) =e(ΔEai /kT) . In the equation, K(ai) is the adhesion retention factor of a chemical group, ΔE(ai) represents the increased chromatographic adhesion energy due to this group and kT expresses the thermal kinetic energy of the molecule contain-ing this group. The dispersive component (γ(dS) ), the electron acceptor component (γ(+S) ) and the electron donor component (γ(−S)) of a solid surface are then calculated from ΔE(ai) . Through correlating the retention time with the adhesion energy, this law expresses mathematically the chromatographic adhesion phenomenon of IGC at the infinite dilution region. This paper also derives a new equation to calculate the retention time of a non-adsorbing probe (dead retention time).