Fabrication of a new carbon paste electrode modified with multi-walled carbon nanotube for stripping voltammetric determination of bismuth(III)

A highly selective and sensitive carbon paste electrode modified with multi-walled carbon nanotubes and 4-[1-(4-methoxyphenyl) methylidene]-3-methyl-5-isoxazolone was used for accumulation and determination of trace amounts of bismuth using the differential pulse anodic stripping voltammetric method. The analytical procedure consisted of a closed-circuit accumulation step onto the modified carbon paste electrode. An anodic peak related to the oxidation of accumulated Bi(0) on the electrode surface was observed at about −0.05 V. The calibration curve was linear in the range of 1–400 μg L−1. The limit of detection was 0.2 μg L−1 and the relative standard deviations for seven replicated determinations at 30, 100 and 300 μg L−1 of bismuth were 3.6, 2.4 and 1.6%, respectively. The modified electrode was applied for the determination of bismuth in pharmaceutical, biological and several water samples. The accuracy and precision of results were comparable to those obtained by the graphite furnace atomic absorption spectroscopy method