Polypyrrole-Hemicellulose Composite Based Electrochemical Sensor for Pb(II) Detection and Quantification in Water

A screen-printed carbon electrode SPCE was modified by the incorporation of polypyrrole (Ppy), as a conductive polymeric matrix and hemicellulose extract from Cactus as a hydrophilic biopolymer. This polypyrrole-hemicellulose composite film (Ppy-HEM@SPCE) was designed for the selective and sensitive detection of Pb(II) trace in aqueous media by square wave anodic stripping voltammetry (SWASV). The porous structure of the Ppy film immobilized hemicellulose homogeneously, providing an even distribution of hydroxyl and carboxyl groups throughout the coating. These functional groups allowed the coordination of Pb(II) ions. The Ppy-HEM@SPCE composite film was characterized by different electrochemical and physicochemical techniques revealing the efficient association and improved coordination properties. Under optimized conditions, a linear relationship was obtained between the redox current and metal ion concentrations ranging from 1 pM to 1 μM and a detection limit of 1 pM was determined. The Ppy-HEM@SPCE composite film demonstrated excellent repeatability, reproducibility as well as long-term stability and potential of regeneration. In addition, the detection of Pb(II) was successfully performed in various real water samples as demonstrated by comparison with ICP/MS as a classical detection method.