Advanced detection of the protozoacide dimetridazole in complex fluids using cassiterite nanoparticles incorporated carbon black composite

Dimetridazole (DMT), a nitroimidazole used in veterinary medicine for treating protozoan infections, poses significant carcinogenic and mutagenic risks, necessitating precise monitoring to ensure food safety. We report the development of an advanced electrochemical sensor based on a glassy carbon electrode (GCE) modified with a nanostructured cassiterite (SnO₂)/carbon black (CB) composite, synthesized via hydrothermal and sonochemical techniques. The sensor benefits from SnO₂'s high electrical conductivity, chemical stability, and large bandgap, while CB enhances its performance with superior conductivity. Characterization through various techniques confirmed the composite's nanostructured morphology with an average particle size of 18 nm. Electrochemical analyses revealed a limit of detection (LOD) of 0.004 μM, a limit of quantification (LOQ) of 0.011 μM, and a wide linear range from 0.29 to 204.6 μM. The sensor demonstrated excellent repeatability and reproducibility, with a relative standard deviation (RSD) of 1.6 % and 2.3 %. It also exhibited notable storage stability, retaining 95.8 % of its initial response after 12 days. Real sample analyses showed impressive recovery rates of 97.5 % to 106.4 % for DMT in complex fluids such as food products, biological fluids, synthetic fluids, and environmental samples.