SEPARATION OF ALKYLPHENOLS BY GAS CHROMATOGRAPHY USING DERIVATIZED CYCLODEXTRINS AS STATIONARY PHASES

Abstract

The single-run separation of twenty-two underivatized C0-C3 alkylphenols was studied by capillary gas chromatography using three derivatized cyclodextrins mixed in polysiloxane as stationary phases. These derivatized cyclodextrins were hexakis(2,3-di-O-acetyl-6-O-tert-butyldimethylsilyl)-alpha-cyclodextrin (ASiAc), heptakis(2,3-di-O-acetyl-6-O-tert-butyldimethylsilyl)-beta-cyclodextrin (BSiAc) and octakis(2,3-di-O-acetyl-6-O-tert-butyldimethylsilyl)-gamma-cyclodextrin (GSiAc). The results showed that three cyclodextrin-based stationary phases could be used to separate the 22 alkylphenol mixture. However, it could be suggested that the size of cyclodextrin ring affect the separation. Among three stationary phases, the medium-size BSiAc gave the best single-run separation with only two co-eluted compounds. The mixture could be separated in 8.8 minutes using a 15 m long, 0.25 mm i.d. column and a temperature program from 70-128 °C at 10 °C/min, held for 2 min; then to 220 °C at 30 °C/min. Moreover, direct analyses of the mixture without prior derivatization gave acceptable peak shapes on these three columns.