Experimental verification of some theoretical considerations on preparative separation with orthogonal pressurised planar electrochromatography.

• The entire OPPEC separation process can run in a fully on‐line operating mode. • There is good agreement between theory and experiment. • OPPEC periodic mode separates substances with equal electrophoretic mobility. • Successful micro-preparative separation of a real post-reaction mixture was conducted. • Advantage of OPPEC vs HPLC for productivity and eluent consumption is possible. This paper reports for the first time the coupling of a two-dimensional separation technique known as orthogonal pressurised planar electrochromatography (OPPEC) with on-line UV/VIS detection. It establishes the efficiency characteristic of a planar column used in OPPEC. The studies show that in OPPEC, all separation steps (mixture introduction, separation, and detection) can run successfully as non-separate operation, much like in HPLC, and the planar column has itself good efficiency, ensuring a relatively low plate height value. In its use, some findings of the previously proposed theoretical model concerning optimisation of preparative separation of components with the same electrophoretic mobility are verified – showing that there is a good agreement between theory and experiment. The paper also demonstrates by means of a specific example of separation of a post-reaction mixture obtained after synthesis of valine diastereomers that OPPEC can be a powerful tool used in preparative separation in that it can achieve much higher separation productivity and significantly lower eluent consumption than when using column chromatography techniques. [ABSTRACT FROM AUTHOR]