Fabrication of S and O-incorporated graphitic carbon nitride linked poly(1,3,4-thiadiazole-2,5-dithiol) film for selective sensing of Hg2+ ions in water, fish, and crab samples.

Screen-printed carbon electrodes (SPCE) were modified with sulfur and oxygen-incorporated graphitic carbon nitride (S, O-GCN) linked poly(1,3,4-thiadiazole-2,5-dithiol) film (PTD) through thioester linkage. The promising interaction between the Hg2+ and modified materials containing sulfur as well as oxygen through strong affinity was studied. This study was utilized for the electrochemical selective sensing of Hg2+ ions by differential pulse anodic stripping voltammetry (DPASV). After, optimizing the different experimental parameters, S, O-GCN@PTD-SPCE was used to improve the electrochemical signal of Hg2+ ions and achieved a concentration range of 0.05-390 nM with a detection limit of 13 pM. The real-world application of the electrode was studied in different water, fish, and crab samples and their obtained results were confirmed with Inductive Coupled Plasma - Optical Emission Spectroscopy (ICP-OES) studies. Additionally, this work established a facile and consistent technique for enhancing the electrochemical sensing of Hg2+ ions and discusses various promising applications in water and food quality analysis.