Effect of chromatographic conditions on separation and system efficiency for HPLC of selected alkaloids on amide C16 stationary phases

Retention data for 29 alkaloids were determined on an amide embedded RP silica column with different aqueous mobile phases – mixtures of acetonitrile with water, mixtures of acetonitrile with aqueous buffers of pH 3 or pH 7.8, and mixtures of acetonitrile with aqueous buffers containing ionpair reagents or silanol blockers. Improved peak symmetry and separation selectivity for basic solutes were observed when ion-pair reagents or silanol blockers were used as mobile phase additives. The best separation selectivity and most symmetric peaks for the alkaloids were obtained by use of mobile phases containing diethylamine. The effect of diethylamine concentration on retention, peak symmetry, and theoretical plate number was investigated.