Hypercrosslinked styrene-based monoliths possessing high specific surface area have proven to enable good separations of small molecules in isocratic reversed phase mode [1].However, these monoliths are hydrophobic and cannot be used for the separation of hydrophilic and polar compounds.We are in pursuit of new stationary phases for chromatography which are suitable for a wide range of separation but still possess the advantages of polymer-based monolithic columns compared to columns packed with silica based particles.Specifically, we exploit the advantages of low back pressure and work in a wide pH range that permit use of aqueous eluents for mixed mode separations.Hypercrosslinked styrene-based monolithic capillary columns were modified by sulfonation with concentrated sulfuric acid and oxidation with potassium permanganate, respectively.After these modifications, the columns possess sulfonic acid and carboxylic acid groups, respectively, whereby the surface is rendered more hydrophilic.The columns are capable of separating both hydrophobic compounds such as benzene, toluene, and ethylbenzene as well as hydrophilic compounds including uracil and cytosine with a retention order similar to that of reversed phase liquid chromatography and exhibit efficiencies of 30,000-40,000 theoretical plates per meter.