Simultaneous determination of ascorbic acid, dopamine and uric acid using a glassy carbon electrode modified with the nickel(II)-bis(1,10-phenanthroline) complex and single-walled carbon nanotubes.

The authors report that a glassy carbon electrode modified with the [Ni(phen)] complex and single-walled carbon nanotubes represents a useful sensor for simultaneous determination of ascorbic acid (AA), dopamine (DA) and uric acid (UA). The material was characterized by scanning electron microscopy, and the electrode by cyclic voltammetry and electrochemical impedance spectroscopy. The experiments showed that this electrode responds to AA, DA and UA, best at working potentials of 0.130 V, 0.334 V, 0.486 V (vs. SCE), over the wide linear ranges from 30 to 1546 μM (for AA), 1 to 780 μM (for DA), and 1 to 1407 μM (for UA). The respective detection limits are 12 μM, 1 μM and 0.76 μM at an S/N ratio of 3. The modified electrode was successfully applied to the determination of AA, DA and UA in real samples. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]