Application of Metal-Organic Frameworks in Chromatographic Separation

Metal-organic frameworks (MOFs) are synthesized via the self-assembling combination of organic ligands and inorganic metals or metal-oxo units (secondary building units, SBUs) using strong bonds to form a porous open crystalline. Because of their outstanding thermal stability, chemical stability and designability, MOFs are successfully applied in various fields, such as gas absorption, separation, purification, catalysis, as well as templates for various functional materials. MOFs are also used as column materials for gas or liquid chromatography separation. In this paper, the studies about MOFs used as stationary phases in gas chromatography and high-performance liquid chromatography were reviewed according to the separated various analytes. We summarized the separation effects of different MOFs for different substances, especially focusing on the separation mechanism of MOFs. The key influence factors on the chromatographic separation, such as pore diameter, functional groups and unsaturated metal sites of MOFs, were expounded. Then, the challenges of MOFs as stationary phases in gas and high-performance liquid chromatography were discussed, which include the mechanism, chiral separation, the limited MOFs in chromatographic separation. The future research in this field should focus on defining separation mechanism, improving their stability and synthesizing the MOFs with special function.