Biomass tomato pomace as a fluorescence probe for determination of toltrazuril in veterinary pharmaceuticals and milk samples.

Toltrazuril (TTZ), which is categorized as an antiparasitic agent, is utilized within the domain of veterinary medicine through administration in drinking water; however, it is predominantly employed to combat a transmissible amoebic infection that affects livestock, particularly poultry, in environments characterized by elevated temperatures and high humidity. Nitrogen-doped carbon quantum dots (N-CQDs) have been synthesized utilizing microwave techniques, incorporating tomato pomace waste as a low-cost biomass precursor to prepare N-CQDs, which were applied for the first time as a fluorescence probe for TTZ determination in veterinary pharmaceuticals and milk samples. This research introduces a novel methodology for the sensitive determination of TTZ employing a static quenching mechanism, with LOD of 0.03 µM within a linearity of 0.15-25.0 µM. Moreover, the proposed fluorescence probe has potential practical application value for antibiotic residue safety regulation in animal-derived food. Furthermore, a standardized milk extraction procedure was created for spiked milk samples from cattle. This technique makes it easier to identify TTZ in milk after extraction using the suggested method. The environmental sustainability of the proposed method was assessed using classical greenness metrics (AGREE, MoGAPI, and Analytical Eco-Scale) together with complementary lifecycle-oriented sustainability tools (CaFRI, EPPI, and SAMI), enabling integrated evaluation of procedural greenness, carbon footprint, and overall sustainability performance.