Changes in the carrier gas flow rate have been used to separate bulk d
iffusion and surface adsorption contributions from total retention dat
a in inverse gas chromatographic experiments. The polymer was a styren
e/4-vinylpyridine diblock copolymer, and experiments were carried out
at temperatures both below and above its T-g. It has been found that b
oth contributions coexist and neither one is negligible at normal flow
rates of the carrier gas. The diffusion coefficients at infinite dilu
tion, or zero concentration, of n-alkane vapors in the polymer phase h
ave been estimated from the separated bulk diffusion data and from the
retention times for the adsorption of the probes on the polymer surfa
ce.