Modification of carbon ceramic electrode prepared with sol-gel technique by a thin film of chlorogenic acid: application to amperometric detection of NADH.
The carbon ceramic electrode prepared with sol-gel technique is modified by a thin film of chlorogenic acid (CGA). By immersing the carbon ceramic electrode in aqueous solution of chlorogenic acid at less than 2s a thin film of chlorogenic acid adsorbed strongly and irreversibly on the surface of electrode. The cyclic voltammetry of the resulting modified CCE prepared at optimum conditions shows a well-defined stable reversible redox couple due to hydroquinone/quinone system in both acidic and basic solutions. The modified electrode showed excellent electrocatalytic activity toward NADH oxidation and it also showed a high analytical performance for amperometric detection of NADH. The catalytic rate constant of the modified carbon ceramic electrode for the oxidation of NADH is determined by cyclic voltammetry measurement. Under the optimised conditions the calibration curve is linear in the concentration range 1-120mum. The detection limit (S/N = 3) and sensitivity are 0.2muM and 25nAmuM(-1).The results of six successive measurement-regeneration cycles show relative standard deviations of 2.5% for electrolyte solution containing 1mM NADH, indicating that the electrode renewal gives a good reproducible and antifouling surface. The advantages of this amperometric detector are: high sensitivity, excellent catalytic activity, short response time t < 2s, remarkable long-term stability, simplicity of preparation at short time and good reproducibility.
Salimi
Abdollah
A
(a)Department of Chemistry, Faculty of Science, Kurdistan University, P.O. Box 416, Sanandaj, Iran.
Hallaj
Rahman
R
Ghadermazi
Mohammad
M