Mixed chiral stationary phase containing modified resorcinarene and β-cyclodextrin selectors bonded to a polysiloxane for enantioselective gas chromatography

Both a resorcinarene with pendant l-valine diamide groups (used as hydrogen-bonding selector) and a permethylated β-cyclodextrin (used as inclusion-type selector) were chemically bonded to poly(hydromethyl)dimethylsiloxane in a one-pot reaction via Pt-catalyzed alkene hydrosilylation. This novel mixed chiral stationary phase (mixCSP) named Chirasil-Calixval-Dex resembles a combination of the known chiral stationary phases (CSPs) Chirasil-Calixval and Chirasil-Dex and it was used successfully in enantioselective gas chromatography toward a unified enantioselective GC separation system. It is demonstrated that Chirasil-Calixval-Dex retains the individual enantioselectivites of the single components. Thus the enantiomers of apolar hydrocarbons as well as polar amino acid derivatives can be separated with the mixed CSP.