Disposable amperometric sensor for neurotransmitters based on screen-printed electrodes modified with a thin iridium oxide film.
Potential cycling in the range from -0.2 to +1.2 V is used for the electrodeposition of hydrous iridium oxide films onto a screen-printed electrode from a saturated solution of alkaline iridium(III) solution. The iridium oxide redox couple shows a stable and obvious reversible redox, with the formal potential being pH dependent in the range 1-14. The properties, stability and electrochemical properties of iridium oxide films were investigated by cyclic voltammetry. A modified electrode showed excellent catalytic activity toward the oxidation of neurotransmitters (catecholamines) over a wide pH range (2-8). The electrocatalytic behavior is further exploited as a sensitive detection scheme for adrenaline and dopamine by hydrodynamic amperometry. Under the optimized conditions, the calibration curves are linear in the concentration range 0.1-70 and 0.1-15 microM for dopamine and adrenaline determination, respectively. The detection limit and sensitivity are 30 nM and 30 nA/microM for adrenaline and 15 nM and 80 nA/microM for dopamine. Finally, the analytical performance of the modified electrode was demonstrated for the elimination of interference by uric acid in catecholamines determination when present in a 1000-fold concentration excess.
Salimi
Abdollah
A
Department of Chemistry, Kurdistan University, Sanandaj, Iran. absalimi@yahoo.com
Alizadeh
Vali
V
Compton
Richard G
RG
D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D002384:Catalysis; D004209:Disposable Equipment; D004298:Dopamine / Q000032:analysis / Q000737:chemistry; D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods; D004566:Electrodes; D004837:Epinephrine / Q000032:analysis / Q000737:chemistry; D007495:Iridium / Q000737:chemistry*; D018377:Neurotransmitter Agents / Q000032:analysis* / Q000737:chemistry; D010084:Oxidation-Reduction; D014527:Uric Acid / Q000737:chemistry
D018377:Neurotransmitter Agents; C044458:iridium oxide; D014527:Uric Acid; D007495:Iridium; D004298:Dopamine; D004837:Epinephrine