Enhanced electrochemiluminescence from luminol at multi-walled carbon nanotubes decorated with palladium nanoparticles: A novel route for the fabrication of an oxygen sensor and a glucose biosensor

Incorporation of palladium nanoparticles on the surface of multi-walled carbon nanotubes and modification of glassy carbon electrode with the prepared nano-hybrid material led to the fabrication of a novel electrode. The modified electrode showed attractive electrocatalytic activity and sensitizing effect on luminol-O-2 and luminol-H2O2 electrochemiluminescence (ECL) reactions at neutral media. The sensitized luminol-O-2 and luminol-H2O2 reactions were successfully applied for the ECL determination of dissolved O-2 and glucose. respectively. Under the optimal conditions for lurninol-O-2 system, the ECL signal intensity of luminol was linear with the concentration of dissolved oxygen in the range between 0.08 and 0.94 mM (r= 0.9996) and for luminol-H2O2 system, the ECL signal intensity of luminol was linear with the concentration of glucose in the range between 0.1 and 1000 mu M (r = 0.9998). The limits of detection (S/N = 3) for dissolved oxygen and glucose were 0.02 mM and 54 nM, respectively. The relative standard deviations (RSD) for repetitive measurements of 0.50 mM oxygen (n = 10) and 10 mu M glucose (n =30) were 3.5% and 0.3%. respectively. Also, under the optimal conditions for luminol-H2O2 system, the ECL signal intensity of luminol was linear with the concentration of H2O2 in the range between 1 nM and 0.45 mM (r= 0.9997). The limit of detection (S/N =3) for H2O2 detection was 0.5 nM and the relative standard deviation for repetitive measurements of 10 mu M H2O2 (n = 10) was 0.8%. (C) 2011 Elsevier B.V. All rights reserved.