Copper electrodes for stable subpicomole detection of carbohydrates in high-performance liquid chromatography

Abstract A new pretreatment of copper (Cu) electrodes used for catalytic oxidation of carbohydrates is presented, which involves superficial polishing of the electrochemically-oxidized Cu electrode and then air-oxidation at 100°C for 3 h. This pretreatment allows highly sensitive and stable detection of carbohydrates at 0.45 V (vs. Ag/AgCl/Sat. KCl) in anion-exchange high-performance liquid chromatography. Glucose was detected at concentration levels as low as 0.2 pmole with a dynamic range up to 10 000 p mole over a period of 1 month. The change in the electrode surface state during the pretreatment is discussed from the electrochemical point of view.