Fluorescent detection of S2− based on ZnMOF-74 and CuMOF-74

The detection of S 2− is of great significance because excess S 2− can lead to a variety of serious physiological diseases. Here, two metal-organic frameworks (MOFs), ZnMOF-74 and CuMOF-74, were synthesized by using 2,5-dihydroxy terephthalic acid with strong fluorescence as organic ligand and Zn 2+ or Cu 2+ as central coordination ions for S 2− detection. Both as-prepared ZnMOF-74 and CuMOF-74 displayed nanospheres with a diameter of about 100 nm. Under the excitation of 353 nm, the ZnMOF-74 had a characteristic emission peak at 537 nm and the CuMOF-74 had a characteristic emission peak at 528 nm under excitation of 356 nm. The interaction of S 2− and Zn 2+ weakened the fluorescence of ZnMOF-74 but the interaction of S 2− with Cu 2+ to form CuS restored the fluorescence of CuMOF-74, so the ZnMOF-74 and CuMOF-74 were exploited as a fluorescent nanosensor for sensing S 2− . The ZnMOF-74 sensor has a good linear range of 19.6 nmol L −1 -90.0 μmol L −1 , and the limit of detection was as low as 6.53 nmol L −1 . The CuMOF-74 sensor has a good linear relationship with I I 0 in the S 2− concentration range of 1.50 nmol L −1 -125 μmol L −1 , and the limit of detection was 1.50 nmol L −1 . The proposed ZnMOF-74 and CuMOF-74 sensor could also detect S 2− in actual samples.