A highly sensitive and stable detection of acetylcholine by HPLC-osmium-horseradish peroxidase redox polymer electrode coated on a gold radial flow ring disk

To detect a low level of acetylcholine (Ach) output in the dialysate of rat frontal cortex, osmium-peroxidase redox polymer modified gold-ring disk electrode (OsHRP-RDE) was fabricated in high-performance liquid chromatography (HPLC)-electrochemical detection (ECD). In comparison with platinum electrode, the sensitivity of acetylcholine detection by Os-HRP-RDE was stable during a day, the coefficient of variation was 0.95%, and the decrease of the sensitivity for 1 week was 5.4%. The Os-HRP-RDE could detect lower than 3 fmol of acetylcholine. The present technique, in the absence of acetylcholinesterase (AchE) inhibitor, is useful to facilitate physiological investigations of cholinergic neuronal activity in the brain.