With the rapid advancement of global healthcare and economic development, the antimicrobial resistance (AMR) and antibiotic-residue contamination in aquatic environments and their implications for human health have become a critical issue worldwide. Consequently, the development of highly efficient, sensitive and field-deployable analytical techniques for determining antibiotic concentrations in water bodies has become more crucial than ever before, particularly for rapid screening in complex environmental matrices. In this thesis, a series of highly sensitive, selective electrochemical sensors with excellent long-term stability for Metronidazole (MTZ), Sulfanilamide (SFD), Flutamide (FLD), Sulfamerazine (SRZ), and Sparfloxacin (SPAR) were developed, addressing the overall research question of whether structurally tunable hybrid interfaces can provide sensitive, selective, and stable antibiotic detection across multiple analytes. The sensors involved modifying glassy carbon electrodes (GCE), screen-printed electrodes (SPE), and carbon cloth (CC) with diverse catalyst materials to increase surface area, improve electron transfer and ensure stability, with a comparative design strategy spanning laboratory and deployable electrode formats. The sensors were then used to detect antibiotics in real aquatic environments and in artificial urine, thereby evaluating practical matrix compatibility and selectivity beyond ideal electrolyte systems. These nanocomposites incorporate two-dimensional transition metal dichalcogenides (TMDs), spinel oxides, and carbon-based materials (reduced graphene oxide (rGO), carbon particles (CPs), and carbon nanofibres (CNFs)), and the novelty of this thesis lies in systematically comparing how these TMD/spinel/carbon materials, prepared via simplified and partially green processing routes, control electroanalytical performance across different targets and electrode substrates. Excellent results were achieved in electrochemical detection experiments: (1) Exfoliated molybdenum disulfide (MoS2) demonstrated detection of MTZ across an exceptionally broad range from 40 nM to 2000 μM, addressing the Chapter 3 question of whether exfoliated MoS2 can deliver high sensitivity and wide-range MTZ detection; (2) Reduced graphene oxide/graphite (rGO/G) demonstrated superior performance to pure reduced graphene oxide, and an impressive limit of detection (LOD) of 86 nM was achieved for SFD, addressing the Chapter 4 question of whether rGO/G coupled with exfoliated MoS2 can improve SFD sensing; (3) Carbon particles (CPs) and tungsten disulfide (WS2) platelets synergistically detected FLD with an LOD of 0.74 nM, addressing the Chapter 5 question of CPs-WS2 interfacial synergy for FLD electroanalysis; (4) Cerium oxide (CeO2) nano-powders sprinkled over the spinel provided excellent stability and the LOD for SRZ was 13.8 nM, addressing the Chapter 6 question of stable and selective SRZ sensing using a CeO2/spinel/WS2; and (5) a novel sustainable spinel was synthesised and applied to two distinct electrodes, giving LODs of 49.0 nM with cerium ferrite (CeFe2O4) spinel oxide supported by CNFs on GCE and 14.0 nM when immobilised on CC, addressing the Chapter 7 question of transferable SPAR detection on conventional and flexible substrates. Moreover, these composites not only detect these diverse antibiotics in water but also maintain selectivity towards corresponding antibiotics when deployed in complex real-world aquatic environments, demonstrating the practical potential of rationally engineered TMDs/spinel/carbon materials electrochemical platforms for environmental pharmaceutical monitoring.