Micro-2D-TLC separation of phenolics in some species of mint and their fingerprints on diol bonded polar stationary phase

Micro-thin-layer chromatography in two dimensional (2D-mTLC) mode in normal and reversed phase systems by use of diol bonded stationary phase was applied to make fingerprints of 11 species of Mentha genus and two finished pharmaceutical products. Nonaqueous eluents (propan-2-ol or ethyl acetate dissolved in n-heptane) were used in normal phase systems. Mixtures of acetonitrile with water were used in reversed phase chromatographic systems. Optimization of one dimensional systems was performed by determining of R sub(F) vs. composition of mobile phases dependencies for standards occurring in various species of Mentha. Most selective eluents were chosen to optimize two-dimensional systems by creating R sub(F) in normal-phase (NP) systems vs. R sub(F) in reversed-phase (RP) systems correlations. 2D-mTLC on diol polar bonded stationary phase were optimized to separate phenolic compounds and make fingerprints of examined plant materials and this method was never applied earlier in the chromatographic analysis.