Novel approach to bismuth modifying procedure for voltammetric thick film carbon containing electrodes

The novel bismuth modifying technique for disposable thick film carbon containing sensors (TFCC) by means of a surface synthesis of the modifier (bismuth phosphate) have been developed. The optimal composition and the method of cathodic reduction (“activation”) of the modifying BiPO4 layer has been proposed. These conditions provided the structure of a modifying layer with the bismuth nano particles of size less than 0.1 μm. On the important analytical parameters (sensitivity, accuracy, tolerance to surfactant fouling effect, particularly for Zn), sensor developed (TFCC/BiPO4) surpasses TFCC with electrolytic bismuth films. The detection limit of 8 nM for zinc, 4 nM for cadmium and 2 nM for lead was achieved after a 2 min accumulation. Therefore, the developed non-toxic and low cost disposable sensor excludes the necessity of mechanical pretreatment of a working surface and can be used in field, laboratory and automatic systems for environmental monitoring (at the trace level inclusive).