Abstract
High-Performance Liquid Chromatography (HPLC) separation mechanisms of raspberry ketone and caffeine on phenyl columns (PhE and PPF) are described. The pi-pi interactions played major role in separation phenomenon. PhE column resulted into better separation than PPF due poor pi-pi interactions in later column. Fast, reproducible, selective, and effective HPLC method was developed for analyses of ketone and caffeine in pharmaceutical preparation. The columns used were Sunniest PhE (phenyl) (250x4.6mm, 5.0 mu m) and Sunshell PFP (100x4.6mm, 2.6 mu m) of Chromanik Japan. The mobile phase used was water-acetonitrile (60:40, v/v, at different pH values) at 1.0mL/min flow rate. The detection was at 280nm with 27 +/- 1 degrees C as working temperature. The ranges of capacity (k), separation (alpha), and resolution (R-s) factors at different pH values on both columns were 2.60-5.10, 1.32-1.60, and 3.22-4.28, respectively. The values of limit of detection (LOD) and limit of quantitation (LOQ) of raspberry ketone and caffeine on both columns ranged from 5.0 to 20.0 and 7.0 to 25.0, respectively. The developed mechanistic aspect is useful for designing separation strategies of other molecules on these phenyl columns. The reported method may be used for quality control in industries and government organizations. Besides, fast analyses may be carried out in various food products.