Determination of carbohydrates in honey and milk by capillary electrophoresis in combination with graphene–cobalt microsphere hybrid paste electrodes

•Graphene–cobalt microsphere hybrid paste electrode was fabricated.•The electrode exhibited high electrocatalytic activity towards carbohydrates.•The electrode was applied in the detection of capillary electrophoresis.•Carbohydrates in honey and milk were determined by the electrode. A graphene–cobalt microsphere (CoMS) hybrid paste electrode was developed for the determination of carbohydrates in honey and milk in combination with capillary electrophoresis (CE). The performance of the electrodes was demonstrated by detecting mannitol, sucrose, lactose, glucose, and fructose after CE separation. The five analytes were well separated within 9min in a 40cm long capillary at a separation voltage of 12kV. The electrodes exhibited pronounced electrocatalytic activity, lower detection potentials, enhanced signal-to-noise characteristics, and higher reproducibility. The relation between peak current and analyte concentration was linear over about three orders of magnitude. The proposed method had been employed to determine lactose in bovine milk and glucose and fructose in honey with satisfactory results. Because only electroactive substances in the samples could be detected on the paste electrode, the electropherograms of both food samples were simplified to some extent.