Metal-Organic Frameworks as Stationary Phase in Chromatography

Liquid chromatography, and in a broader perspective, chromatography, is one of the most commonly used and powerful analytical methods, allowing the separation and identification of up to thousands of components in complex mixtures, e.g. biological samples. The impact of this technique in areas, such as protein analysis, pharmaceutical analysis, forensic science, environmental health and food science etc. cannot be overstated. Thereby, the development of new kind of stationary phases is of tremendous importance to meet the challenges of fast and efficient separations for a wide range of samples. Fundamental research to improve column performance contributes to the advancement of better and more powerful columns and separation methods. Therefore, new classes of porous adsorbents have been evaluated, among which the metal-organic frameworks (MOFs) offer great promise in various applications in the broad field of chemistry. A combination of their chemical and structural properties makes these sorbents worthwhile to study them as stationary phase adsorption based separations.
In this thesis, a number of microporous MOFs are investigated as separation medium in gas chromatography (GC), high performance liquid chromatography (HPLC) and capillary liquid chromatography (capillary LC). UiO-66, UiO-66-Me, ZIF-68, MIL-53(Al) and MIL-125(Ti) are selected based on features such as stability, polarity, separation ability, pore structure, and crystal morphology. Secondary, MOF based composite particles, Cu(CHDA)@SiO2 and UiO-66@carbon, are tested. All of the materials were synthesized at the Center for Surface Science
and Catalysis (KU Leuven) in the frame of a collaboration within the SBO ‘MOFShape’ project, aiming at the shaping of MOFs for adsorption, energy and catalysis applications. The adsorptive properties of these materials were studied at the Department of Chemical Engineering (CHIS, VUB).