RETENTION ON MIXED CYCLODEXTRIN POLYSILOXANE STATIONARY PHASES IN CAPILLARY GC - EVIDENCE FOR THE INTERACTION OF CYCLODEXTRIN AND POLYSILOXANE/

The dependence of the retention on stationary phases consisting of mix tures of a cyclodextrin (perpentyl-beta-cyclodextrin) and a polysiloxa ne (cyanopropyl-7%-, phenyl-7%-methyl-86%-or OV-1701) was investigated as function of the cyclodextrin concentration. In order to study the effect of mixing, the data on the mixed stationary phases were compare d with those obtained on pure OV-1701 and perpentylated beta-CD and on coupled columns, individually coated with the pure phases. The validi ty of the retention model proposed in the literature by Schurig and co -workers was checked. Deviation from linearity was observed for some r acemates. A possible explanation of the deviation is presented and a m ore general retention model on mixed cyclodextrin-polysiloxane phases is proposed.