Surface Improvement of Glassy Carbon Electrode Anodized in Triethylene Glycol and Its Application to Electrochemical HPLC Analysis of Protein-Containing Samples

Abstract

In order to improve electrochemical performance of a glassy carbon (GC) electrode anodized in triethylene glycol (TEG), a GC electrode was anodized in H2O prior to TEG anodization. The effect of this pretreatment was evaluated by comparing electrochemical responses of acetaminophen on HPLC using the following electrodes: a GC electrode anodized in both H2O and TEG (double modified GC electrode); an unmodified GC electrode; GC electrodes anodized in either H2O or TEG. HPLC was carried out for samples containing uric acid and acetaminophen with or without various proteins. The results reveal that the double modified GC electrode has satisfactory sensitivity, reproducibility, and durability in electrochemical detection of acetaminophen by HPLC, compared with other electrodes. In order to demonstrate the advantage of the double modified GC electrode, analysis of acetaminophen from a urine sample was performed by HPLC without carrying out any tedious procedures such as the removal of proteins. In addition, electrochemical analyses of various compounds were performed using the double modified GC electrode in a near-flow injection mode, suggesting that the electrode has potential applications for HPLC analysis of biologically important cationic and neutral compounds.