Determination of molar heats of absorption of enantiomers into thin chiral coatings by combined IC-calorimetric and microgravimetric (QMB) measurements: II. Thermodynamics of enantioselectivity in modified cyclodextrins

A combination of microgravimetric and microcalorimetric measurements was developed for the investigation of enantioselective gas–surface interaction. The sorption behaviour of the two enantiomers of methyl-2-chloropropionate was investigated at polydimethylsiloxane (PDMS) as an achiral receptor and octakis (3-O-butanoyl-2,6-di-O-n-pentyl)-γ-cyclodextrin (Lipodex E®) as a chiral receptor. The microgravimetric and microcalorimetric results are described by a suitable thermodynamic model providing the thermodynamic data of the absorption process. These data are discussed in terms of the mechanism of chiral recognition and compared to literature data derived from gas chromatographic results by the van’t Hoff method.