Metal-Organic Framework Enhances Aggregation-Induced Fluorescence of Chlortetracycline and the Application for Detection

The development of an analytical method for selective and sensitive detection of chlortetracycline (CTC), an often overused broad spectrum antibiotic, is important and challenging in environmental and health monitoring. This paper reports a zinc based metal-organic framework of pyromellitic acid (Zn-BTEC), which has been found to greatly enhance the aggregation-induced emission (AIE) of chlortetracycline. The unique emission response of CTC on Zn-BTEC has been extensively examined and applied for the sensitive detection of CTC on the basis of fluorescence intensity of AIE, and a limit of detection (LOD) was estimated to be 28 nM. A rational mechanism has been proposed based on the porous structure of Zn-BTEC, and the CTC molecules would defuse into the rigid MOF structure and assemble or aggregate, leading to fluorescence enhancement of CTC. Interestingly, the Zn-BTEC materials could discriminate CTC from other TC antibiotics with high selectivity. We have further demonstrated that the Zn-BTEC materials are successfully applied for the sensitive and selective determination of CTC in real samples of fish and urine.