A.S. Osipov, E.B. Nechaeva, E.N. Orlov

The aim of this research is to analyze the opportunity to use a monolithic column Chromolith SpeedROD RP-18e 50×4,6 mm for the analysis of isomers of isosorbide mononitrate and isosorbide dinitrate in conditions of isocratic chromatography, and with increasing flow rate of mobile phase. Application of column Chromolith SpeedROD RP-18e 50×4,6 mm reduce the analysis time isosorbide nitrate. The use of mobile phase methanol  water (1:9) provides good separation of the isomers of isosorbide mononitrate (resolution 3.59). Efficiency of separation of isomers of isosorbide mononitrate is comparable to the separation of these isomers on columns C18 250 mm long. With increasing flow rate of mobile phase before 4-5ml/min maximum system pressure should not exceed the working pressure range is usually observed in liquid chromatography. Increasing the flow rate of mobile phase is practically no impairment of the symmetry of the peak of isosorbide dinitrate. However, in this case, there was a marked decrease in the peak height of isosorbide dinitrate. In the application of the mobile phase methanol  water (1:9), the peak height decreased by 17 % when using a mobile phase acetonitrile - water (1:9) peak height decreased by 9.5%.