Preparation and characterization of tentacle-type polymer stationary phase modified with graphene oxide for open-tubular capillary electrochromatography

• A novel polymer stationary phase modified with GO was prepared for OT-CEC.
• Tentacle-type polymer coating was used to enlarge the immobilized amount of GO.
• The eletrochromatographic performance of GO-modified OT column was investigated.
• The GO-GMA@capillary showed great stability and repeatability.
• The GO-GMA@capillary exhibited excellent separation ability.

In this research, a novel organic polymer coated stationary phase modified with inorganic nanomaterial was prepared for open-tubular capillary electrochromatography (OT-CEC). The capillary was developed by covalent attaching graphene oxide (GO) onto the tentacle-type polymer chains grafted capillary which was derivatized with ammonium hydroxide. Scanning electron microscopy (SEM) and Raman spectroscopy provided evidences that the tentacle-type polymer and GO were coated to the capillary inner wall. This novel GO-polymer modified capillary column generated a strong and stable electroosmotic flow (EOF) from anode to cathode with the running electrolytes of pH ranging from 4.0 to 9.0, and showed excellent separation ability toward neutral small molecules, amino acids and ephedrine–pseudoephedrine isomers with resolution higher than 2.30 and column efficiency up to over 170,000 plates/m. The repeatabilities of the GO-GMA@capillary were satisfying with relative standard deviations for intra-day and inter-day runs less than 3.27%, and column-to-column runs less than 7.49%. Additionally, the separation performance of GO-polymer modified capillary was compared with that of the polymer coated capillary and GO coated capillary.