Combining Alkaline Extraction and in Situ Plated Bismuth Film for Reliable Quantification of Zn in Multivitamin Formulations

In this work a bismuth film electrode (BiFE) plated in situ onto glassy carbon was used to quantify Zn2+ in multivitamin formulation samples by square wave anodic stripping voltammetry. For partially water‐soluble multivitamin tablets, an alkaline extraction with 1.0 mol L−1 NaOH aqueous solution was adopted. This procedure was simple, fast and efficient to extracting Zn from sample matrix. Moreover, this procedure was able to make the method less susceptible to interferences from Cu2+, since it remains at extracting vessel as insoluble Cu(OH)2. For fully water‐soluble effervescent tablets, sample pretreatment was not required.