A robust cd-based coordination polymer with high sensitivity for fluorescent detection of cefixime in environmental water and milk samples.

Antibiotic misuse and residues can disrupt ecological balance and compromise food safety, making the development of highly selective and sensitive antibiotic detection methods crucial. In this study, a two-dimensional cadmium-based coordination polymer {[Cd₃(ndda)₃(bpy)₁.₅(H₂O)₃]·H₂O} (CP 1) was successfully synthesized via a solvothermal method and applied for the detection of the widely used antibiotic cefixime (CEX). The structure of CP 1 was systematically characterized using multiple analytical techniques, and its fluorescence properties were investigated. The results demonstrate that CP 1 can rapidly (within 1 min) and selectively identify CEX in aqueous solution even in the presence of interfering substances. The material not only exhibits an excellent detection limit (8.49 nM) but also can be reused for up to five cycles. Based on the structural features of CP 1 and experimental evidence, the fluorescence quenching mechanism is proposed to involve a synergistic effect of competitive absorption (CA) and photoinduced electron transfer (PET). Furthermore, when applied to the detection of CEX in environmental water and milk samples, CP 1 achieved satisfactory recovery rates and low relative standard deviations. This study confirms that CP 1, as a fluorescent probe material, holds significant potential for CEX detection in food safety monitoring and environmental analysis.