Electrochemical determination of hazardous 4-nitrophenol at bismuth sulfide-embedded graphitic carbon nitride nanocomposite-based electrode

In this study, the determination of 4-nitrophenol (4-NTPh) was performed at an electrode matrix consisting of bismuth sulfide and graphitic carbon nitride nanoparticles (g-C 3 N 4 -Bi 2 S 3 NPs) immobilized using a chitosan (Chit) polymeric matrix on a homemade pencil graphite electrode (PGE). The g-C 3 N 4 -Bi 2 S 3 +Chit/PGE modified electrode was obtained via a simple drop-casting method of modification. Structural, morphological, and electrochemical characteristics of both the NPs and the modified electrode were investigated. The g-C 3 N 4 -Bi 2 S 3 +Chit/PGE modified electrode has a limit of detection (LOD) of 41.10 nmol L −1 and a sensitivity of 72 mA mol −1 L. The high selectivity, reproducibility, repeatability, and stability of the new platform enable it to be used in real water samples (river and tap water) with recoveries of 98–99%. Therefore, the novelty of the present work is based on the following approaches: (i) the production of the NPs, as well as the use of inexpensive pencil graphite electrodes, ensures the sustainability of the proposed technology; and (ii) from the best of our knowledge it is the first-time when g-C 3 N 4 -Bi 2 S 3 NPs were used as a sensing platform for 4-NTPh determination in a real water sample.