Surface improvement of glassy carbon electrode anodized in triethylene glycol and its application to electrochemical HPLC analysis of protein-containing samples

order to improve electrochemical performance of a glassy carbon (GC) electr ode anodized in triethylene glycol (TEG), a GC electrode was anodized in H2 O prior to TEG anodization. The effect of this pretreatment was evaluated b y comparing electrochemical responses of acetaminophen on HPLC using the fo llowing electrodes: a GC electrode anodized in both H2O and TEG (double mod ified GC electrode); an unmodified GC electrode; GC electrodes anodized in either H2O or TEG. HPLC was carried out for samples containing uric acid an d acetaminophen with or without various proteins. The results reveal that t he double modified GC electrode has satisfactory sensitivity, reproducibili ty, and durability in electrochemical detection of acetaminophen by HPLC, c ompared with ether electrodes. In order to demonstrate the advantage of the double modified GC electrode, analysis of acetaminophen from a urine sampl e 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-f low injection mode, suggesting that the electrode has potential application s for HPLC analysis of biologically important cationic and neutral compound s.