No abstract

A new 2,3-methylated 3*-monoacetylated 6-O-tert-butyldimethylsilylated beta-CD derivative was synthesized and chemically bonded onto aminopropyl derivatized monolithic silica HPLC columns. In this CD derivative, only one of seven methyl groups in 3-position was substituted by an acetyl group. Its applicability as a chiral stationary phase for HPLC was tested and compared with exclusively 2,3-methylated 6-O-tert-butyldimethylsilylated beta-CD immobilized onto aminopropyl-modified monoliths. Thirty-two chiral compounds from different chemical classes and different functionalities were tested under RP conditions. Fourteen compounds were resolved into their enantiomers by methylated 6-O-tert-butyldimethylsilylated beta-CD. By use of methylated/acetylated 6-O-tert-butyldimethylsilylated beta-CD as the chiral stationary phase 7 analytes were successfully stereodifferentiated.

KEY WORDS: mixed modified cyclodextrins; simultaneous enantioseparation; chiral essential oil compounds chiral stationary phases, using DIME-β-CD and DIAC-β-CD.The aim of this investigation is to create a mixed chiral stationary phase with special separation capabilities for the successful simultaneous stereodifferentiation of chiral compounds from important essential oils. Experimental GC analysisThe analyses were performed on a Carlo Erba Strumentazione GC 6000, Vega Series gas chromatograph, equipped with a split/splitless injector and a flame ionization detector. Data acquisition was performed using a Shimadzu C-R6A integrator. Injector temperature, 250°C; detector temperature, 250°C; injection mode, split 20 ml/min; injection volume, 1 µl (0.02% in tertbutylmethylether); column, Duran glass capillary, 25 m × 0.25 mm i.d., 0.25 µm film thickness, coated with a solution (0.4%) of DIME-β-CD (12.5%), DIAC-β-CD (37.5%) and polysiloxane OV-1701 (50%) in dichloromethane/n-pentane (1:1, v:v). Cyclodextrin syntheses were carried out according to references 3 and 4; carrier gas, H 2 at 50 cm/s; temperature programmed from 40°C (5 min isothermal) at 0.5°C/min to 90°C, then at 2°C/min to 220°C. Column preparation and coatingColumn preparation and coating was carried out according to references 7 and 8.