Porphyrin based metal-organic frameworks as an enhanced fluorescence nanoprobe for highly sensitive detection of sulfite

Development of a facile and effective strategy for highly sensitive detection of sulfite (SO 3 2− ) in food is of great significance to human health. Herein, fluorescent porphyrin-based MOFs (PCN-224) was synthesized and further developed as an enhanced fluorescence sensor for SO 3 2− detection. The fluorescence peak of PCN-224 locates at 664 ​nm. In the presence of SO 3 2− , the acid-base reaction between H 2 PO 4 − and SO 3 2− promotes the generation of PO 4 3− , thus forming Zr-OP bonds and enhancing the fluorescence intensity of PCN-224 at 664 ​nm. Therefore, H 2 PO 4 − is used as an auxiliary agent to construct the sensing system PCN-224/H 2 PO 4 − . The fluorescence enhancement of PCN-224/H 2 PO 4 − shows a good linear relationship in the range of 0.01–18 ​μM and the limit of detection is as low as 3.8 ​nM. In addition, the constructed PCN-224/H 2 PO 4 − sensor system can be successfully used for SO 3 2− detection in the granulated sugar with a recovery ranging from 100.17% to 106.25%, demonstrating the feasibility of PCN-224/H 2 PO 4 − nanosensor for SO 3 2− detection in real sample analysis.