The widespread use of antibiotics in healthcare, agriculture, and veterinary sectors has improved human and animal health but has also resulted in environmental contamination and the rise of antimicrobial resistance (AMR). Conventional wastewater treatment systems are unable to completely remove these contaminants, leaving traces of antibiotics to persist in natural waters which in turn allows the growth of resistant bacteria. Recognised by the World Health Organization as a major global threat, AMR emphasizes the urgent need for sensitive environmental monitoring tools. This thesis presents the development of electrochemical sensors for the detection of nitroimidazole antibiotics, ronidazole (RON), ornidazole (ORZ), dimetridazole (DMZ) and 2-nitroimidazole (2-NIM) in aquatic environments. The sensors are based on advanced hybrid materials, including transition metal dichalcogenides, tellurides, oxides, and carbon nanostructures. Although carbon nanofibers (CNFs) and carbon nanotubes (CNTs) provide high conductivity and stability, their poor aqueous dispersion limits performance. To overcome this, a green non-covalent functionalization using tannic acid (0.85-1.0 mM) and mild sonication (50-60 min) was developed, producing uniformly dispersed CNFs and CNTs with enhanced electron transfer and stability for nanocomposite fabrication. A CNF/WO3/WS2 nanocomposite sensor exhibited excellent sensitivity (0.860 μA μM-1 cm-2), a detection limit of 4.1 nM, and a linear range of 10 nM-260 μM for ORZ detection, with strong selectivity and 14-day stability. Similarly, an exfoliated MoSe2/reduced graphene oxide (rGO) sensor achieved a 4.0 nM LOD and 2.60 μA μM-1 cm-2 sensitivity for DMZ. Nickel telluride (NiTe) nanoparticles enabled RON detection with a 1.5 nM LOD, while a CNF/CNO/CQD nanocomposite achieved an even lower LOD to 0.49 nM. A mixed oxide/MWCNT sensor quantified 2-NIM with sensitivity (0.245 μA μM-1 cm-2) and low LOD (3.7 nM). Overall, this work advances scalable, high-performance electrochemical sensing materials for antibiotic monitoring and water quality assessment.