In this work, a voltammetric sensor was used to monitor the concentration of bismuth extracted from an eutectic alloy of BiSn by aqueous two‐phase system. This strategy is a sustainable and economically viable way of recovering bismuth from secondary sources. In the aqueous two‐phase system (ATPS), biodegradable and non‐toxic constituents dispersed in water (major constituent) are used. For monitoring the extraction, bismuth was determined in the upper phase of the aqueous two‐phase system, which is rich in L35 copolymer, that causes attenuation of the electrochemical signal (anodic peak current). The electrode and operational parameters of the square‐wave anodic stripping voltammetry (SWASV) were evaluated according to the deposition and stripping processes of the bismuth on the surface of the carbon paste electrode (CPE). It was observed a similarity between the electrochemical response of the bismuth extracted by ATPS and with the standard solution of bismuth. The proposed method shows a linear range of 1.29–8.94 μmol L−1, limit of detection (1.07 μmol L−1) and limit of quantification (3.57 μmol L−1) and good precision (RSD%=2.27 %). This method was validated by comparing the results with Flame Atomic Absorption Spectroscopy (FAAS), using statistical tests to verify precision and accuracy. In conclusion, using a voltammetric sensor to monitor the concentration of bismuth extracted by ATPS proved to be an efficient method, in agreement with the concentrations of the referenced method.