Preparation and evaluation of a polydopamine-modified capillary silica monolith for capillary electrochromatography
A novel capillary silica monolith (CSM) with surface modification was prepared for capillary electrochromatography (CEC) by using polydopamine (PDA) as a functional coating. For the preparation of PDA-coated CSM, the ratios of oxidant, reaction time and initial DA concentration were optimized. Under the optimal conditions, PDA–CSM showed excellent separation performance. Acidic and basic small molecules were successfully separated. Furthermore, the potential reactivity of PDA was also investigated. A novel graphene oxide (GO)-modified CSM (GO–PDA–CSM) was prepared by using PDA as a linker and the separation performance was investigated by CEC, which showed good separation efficiency toward alkylbenzenes and ephedrine/pseudoephedrine isomers. Moreover, the GO–PDA–CSM exhibited good repeatability and stability. Compared with CSM and GO-modified CSM without PDA coating, the GO–PDA–CSM significantly improved column separation abilities. The PDA-assisted modification method provided a novel, simple, and versatile method for the functionalization of CSM.