Bismuth film electrode for measuring Zn(II) under less acidic conditions in the presence of cell culture medium and ZnO nanoparticles
A study of bismuth film electrode (BiFE) under less acidic conditions for anodic stripping voltammetric measurements of Zn(II) in complex organic sample, i.e. in the cell culture medium containing ZnO nanoparticles, is presented. The BiFE was prepared in-situ on a substrate glassy carbon electrode in solution containing 0.1 mol L-1 piperazine-N,N‘-bis(2-ethanesulfonic acid) (PIPES) and 0.1 mol L-1 KNO3 as supporting electrolyte, adjusted to pH 6.5, and in the presence of dissolved oxygen. In the model solution, i.e. in the absence of cell culture medium and ZnO nanoparticles, the BiFE revealed good linear response in the examined concentration range of 10–100 µg L-1 Zn(II) with r2 of 0.994, the LOD of 0.14 µg L-1 associated with 120 s accumulation step, and favorable repeatability of 1.7 %. Upon the addition of cell culture medium, the signal of Zn(II) attenuated for ca. 64 %; however, the BiFE still exhibited excellent linear response in the examined concentration range of 10–100 µg L-1 Zn(II) with r2 = 0.999, favorably low LOD of 0.15 µg L-1 after 120 s accumulation, and satisfactory repeatability of 3.0 %. Finally, the applicability of the BiFE combined with the proposed approach was successfully demonstrated through measuring Zn(II) in the cell culture medium containing 5 mg L-1 of ZnO nanoparticles for the purpose of a ZnO nanotoxicological study.