Adsorptive stripping voltammetric detection of daunomycin at a bismuth bulk electrode

The bismuth electrode exhibits similar electrochemical properties as most commonly used toxic mercury electrode and represents a suitable, reliable and also environmentally friendly tool for the detection of electroactive compounds at negative potentials. A wide operational potential window of the bismuth electrode from - 200 mV to - 1400 mV (vs. SCE) was found. Bismuth bulk electrodes (BiBE) are very convenient for sensitive adsorptive stripping voltammetric (AdSV) determination of the drug daunomycin in the nmol/L concentration range. In comparison with gold electrodes, the voltarnmetric signals of daunomycin at the bismuth electrode are higher and very well shaped. An accumulation potential of - 0.65 V (vs. SCE) and accumulation time from 2 to 10 min were found to be optimal conditions for the preconcentration of daunomycin on the bismuth electrode surface. The adsorptive stripping response is linear over '100 - 1000 nmol/L concentration range (for 2 min deposition) and over 10 - 100 nmol/L concentration range (for 5 min deposition) with a detection limit of 5 nmol/L (for 8 min deposition). Repeatability was characterized by relative standard deviation 7.1% (for 10 measurements). The electrode must be regenerated between two consecutive measurements by polishing on a damp paper or by stirring in 96% ethanol for 5 min.