A high-performance fluorescence immunoassay based on pyrophosphate-induced MOFs NH2-MIL-88B(Fe) hydrolysis for chloramphenicol detection

In this work, we firstly found and verified that pyrophosphate (PPi) can form a competitive coordination effect with the metal-organic frameworks (MOFs) NH2-MIL-88B(Fe), causing the MOFs structure to collapse and release diaminoterephthalic acid (NH2-BDC), and then weakening the ligand-metal charge transfer (LMCT) of the MOFs network structure, allowing the original fluorescence of NH2-BDC be recovered. Based on this new principle, synthesized high-stability MOFs NH2-MIL-88B(Fe) were employed as fluorescent signal sources to trace target recognition, and MOFs fluorescent immunoprobes were prepared by chemically coupling anti-chloramphenicol (CAP) monoclonal antibodies via the active ester method (EDC/Sulfo-NHS). A direct competitive fluorescence immunoassay was established for the detection of CAP residues in milk samples, in which the limit of detection (LOD) was 0.028 mu g L-1, the linear range was 0.05-0.75 mu g L-1, and the recovery rate was 91.8%-112.3%. This study employed a simple and time-saving one-step method for releasing fluorescent signals, which was also useful for the rapid and accurate detection of CAP residues.

Automated summary

In this study, we discovered the competitive coordination effect of pyrophosphate on MOFs structure and developed a fluorescent immunoassay for detecting CAP residues. The method is simple and efficient, allowing for rapid and accurate detection of CAP residues.