High resolution HPLC

In order to justify its classification as a “high resolution” technique, HPLC should show an improvement in efficiency by a factor of at least 10, should be easily achievable with separation times of less than 1 h, preferably in the reversed phase mode. This is accomplished by coupling three 25 × 0.46 cm columns packed with 5 μm spherical ROSiL-C₁₈-D silica gel. Details of the method and some typical chromatograms are given.