Recent advances in the preparation and application of mussel-inspired polydopamine-coated capillary tubes in microextraction and miniaturized chromatography systems

Capillary tubes are widely used in micro-devices because of their tubular structure, high efficiency, small dead volume and good flexibility. In micro-devices, such as miniaturized chromatography and solid phase microextraction, capillary tubes play a crucial role as stationary phases, carriers or adsorbents for complex sample analysis. Many strategies have been proposed to improve their performance and extend their application by surface engineering. One of the most promising strategies is mussel-inspired chemistry, polydopamine surface modification, which has become a powerful tool in capillary fabrication and modification, as it provides a versatile platform for the construction of diverse hybrid materials with specific functionalities. This review focuses on recent advances in the fabrication of polydopamine-coated capillary tubes for microextraction and miniaturized chromatography systems. In the first part, the preparation strategies of polydopamine coatings are discussed in detail. Next, the application of polydopamine as a novel capillary coating are described. Finally, a conclusion and the key issues that exist in this emerging field are given. (C) 2018 Elsevier B.V. All rights reserved.