Development of a Sensor Based on Poly(1,2-diaminoanthraquinone) for Individual and Simultaneous Determination of Mercury (II) and Bismuth (III)

Contamination of natural water by mercury (Hg²⁺) and bismuth (Bi³⁺) metal ions have been extensively studied due to their toxic effects. A validated square-wave anodic stripping voltammetry (SW-ASV) method for determining Bi³⁺ and Hg²⁺ ions individually and simultaneously is described. A new electrochemical sensor was constructed using a gold (Au) electrode that has been modified with poly(1,2-diaminoanthraquinone) (p-1,2-DAAQ). Scanning electron microscopy, cyclic voltammetry, and electrochemical impedance spectroscopy were used to characterize the p-1,2-DAAQ/Au modified electrode. Factors such as the polymer film thickness, electrolyte, square wave parameters and preconcentration conditions were optimized to improve the performance of the modified Au electrode. Good linear responses were achieved in the concentration ranges of 1–200 μg L^?1 and 1–50 μg L^?1 forBi³⁺ and Hg²⁺, respectively, and the limits of detection were 0.27 μg L^?1 (Bi³⁺) and 0.29 μg L^?1 (Hg²⁺). The interference study results illustrated the high selectivity of the modified electrode for detection of Bi³⁺ and Hg²⁺. The proposed SW-ASV method was successfully applied for Bi³⁺ and Hg²⁺analyses in different real water samples.