Journal of Chromatography vol:630 issue:1-2 pages:117-122
The suitability of eleven silanol-deactivated reversed phases for the liquid chromatography of erythromycin was investigated. The selectivity and efficiency of each stationary phase were examined. The performance was compared to that of a non-deactivated C18 silica-based reversed-phase material, Hypersil C18 (5 mum). Two types of mobile phases were used, one containing no tetrabutylammonium (TBA) and the other containing TBA. Addition of TBA as a silanol-blocking agent improved the theoretical plate number and symmetry factor of the peaks corresponding to erythromycin A (EA) and erythromycin A enol ether for all the deactivated reversed phases. These results are an indication of the presence of some residual silanol activity in these phases. Separation of erythromycin E and EA was achieved on only two of the eleven phases. The selectivity was always poorer than that obtained in a previously described method using a poly(styrene-divinylbenzene) stationary phase.