Amino−functionalized Fe(III)−Based MOF for the high−efficiency extraction and ultrasensitive colorimetric detection of tetracycline

In order to achieve the simultaneous extraction and detection of tetracycline (TC) in milk, the amino−functionalized Fe−based metal−organic frameworks (NH2−MIL−88B) was synthesized via a solvothermal method with Fe3+ and 2−aminoterephthalic acid (NH2−BDC) as precursor. Thanks to the unique structure of NH2−MIL−88B, it could be used to highly effective extract of TC in milk. More interestedly, the introduced –NH2 could react with –OH from TC by a hydrogen-bonding interaction to cause the electronic interactions that enhances the peroxidase−like activity of NH2−MIL−88B, which result in the enhancement of Fenton reaction by the transfer of the electron between TC and NH2−MIL−88B. Under the optimal testing conditions, the linear absorbance response is well correlated with the TC concentration range of 50–1000 nM, which can reach a low LOD of 46.75 nM. Besides, the sensor exhibits excellent selectivity to TC, and the proposed strategy can also be applied to milk with good recovery (83.33–107.00%). Finally, the NH2−MIL−88B and cellulose acetate (CA) are combined to form nanozyme hybrid membranes through the non−solvent induced phase separation method, which can be used to prepare point−of−care testing (POCT) for rapid and in−situ detection of TC.