Packed-column supercritical fluid chromatography of beta-blockers

Packed-column subcritical and supercritical fluid chromatography (SFC) of a total of 10 beta-blocking drugs was investigated on four stationary phases using CO(2)-methanol based eluents. The stationary phases studied were all bonded silicas and included Diol, aminopropyl, cyanopropyl, and "C1". The SFC of some of these compounds was possible with simple CO(2)-methanol based mobile phases, but in general, it proved to be necessary to add triethylamine as a competing base in order to obtain acceptable peak shapes. The best chromatographic results were obtained on the aminopropyl bonded phase, with good results also seen on the Diol phase. Different selectivities were observed for the Diol and aminopropyl columns.