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Ivkovic B, Karljikovic-Rajic K, Vujic Z and Ibric S
In this paper, the separation of metoprolol tartarate enantiomers using conventional achiral chromatography was followed employing experimental design 24. Design was useful tool in evaluation of chromatographic behavior of enantiomers. For the separation, Supelcosil LC18 4.6 mm × 250 mm, 5 m particle size column was used. UV detection was performed at 275 nm. Because of the large number of factors which can influence chromatographic separation, in preliminary study ″one factor at a time″ method was applied to define values of important factors. As outputs, retention factor, selectivity factor and resolution factors were chosen. Chromatographic behavior of investigated enantiomers was affected by acetonitrile content, chiral modificator content in the mobile phase and flow rate the most, demonstrated by obtained linear models. On the basis of results from screening of experiment, factors with strong influence on the separation, were analyzed in method optimization applying response surface methodology (RSM). The appropriate region of chromatographic behavior of metoprolol tartarate enantiomers was defined using three-D graphs and analysis of variance. The methodology proposed represents an efficient approach in resolving the problem of searching for optimal HPLC chromatographic conditions via experimental design.