Green and facile electrode modification by spark discharge: Bismuth oxide-screen printed electrodes for the screening of ultra-trace Cd(II) and Pb(II)

We report that highly effective electrode modification can be achieved by sparking process between a flat electrode substrate and a tip counter electrode. The concept is introduced by the development of Bi2O3-modified graphite screen printed electrodes (SPEs). SPEs were sparked with a bismuth wire at 1.2 kV under atmospheric conditions. The effect of polarity on the morphology of the sensing surface, bismuth loading and the sensitivity of the resulting sensors for the simultaneous anodic stripping voltammetric determination of Cd(II) and Pb(II) was investigated. Compared with electroplated and various bismuth precursors bulk-modified SPEs, the developed sparked electrodes exhibited considerably lower limit of detection (0.2 mu g L-1, S/N = 3) for each target ion. Therefore, sparking technique offers a facile and green approach for the development of highly sensitive bismuth-based electrodes, and a wide-scope of applicability in the development of metal-modified sensing surfaces. (C) 2014 Elsevier B.V. All rights reserved.