Luminol Electrochemiluminescence by Combining Cathodic Reduction and Anodic Oxidation at Regenerable Cobalt Phthalocyanine Modified Carbon Paste Electrode for Dopamine Detection

Luminol electrochemiluminescence (ECL) generated by coupling the cathodic reduction of dissolved oxygen with subsequent anodic oxidation of luminol at cobalt phthalocyanine modified carbon paste electrode (CoPc-CPE) has been reported for the first time. The luminol ECL generated at CoPc-CPE by scanning potential from-0.3 V to 1.0 V is 250 times greater than that generated by scanning potential from 0 V to 1.0 V. Moreover, the CoPc-CPE exhibited about 16-fold stronger ECL than the bare carbon paste electrode because of the excellent elec-trocatalytic activity of CoPc. The developed ECL system was successfully applied to the efficient sensing of dopamine with a fine linear range from 0.5 mu M to 50 mu M and a detection limit of 8.8 nM at a signal-to-noise ratio of 3 based on the quenching effect of dopamine. The CoPc-CPE exhibits excellent long-term stability during 65 days of storage in the ambient environment.