Current trends in affinity-based monoliths in microextraction approaches: A review

This article reviews the research contributions along the past five years concerning to monolithic materials for the development of affinity-based sorbents in the field of microextraction techniques. The first part of this paper includes an introduction regarding monolithic affinity media and information of different binding agents (such as immunoglobulin-binding proteins, enzymes, lectins, antibodies, aptamers, dyes and immobilized metal ions and nanoparticles, among others) that can act as affinity ligands. Then, the preparation of monoliths and ligand immobilization strategies as well as the different available formats (syringes, pipette tips, spin columns, capillaries, disks and microfluidic devices) for their use in micro-solid phase extraction are mentioned. On the basis of the binding agents used to prepare affinity monolithic-based sorbents, the last part of manuscript includes several analytical and preparative applications of these monoliths for sample preparation covering different fields (analytical chemistry, biotechnology, proteomics, etc.). Current trends and possible future directions of these affinity-based sorbents in sample preparation are also given. (C) 2019 Elsevier B.V. All rights reserved.