A hybrid coumarin-thiazole fluorescent sensor for selective detection of bisulfite anions in vivo and in real samples

A hybrid coumarin-thiazole compound was developed as a novel ratiometric and colorimetric sensor for bisulfite anions. Structure identification of the compound was confirmed by (1)H NMR, (13)C NMR, (1)H,(1)H COSY, heteronuclear single quantum coherence (HSQC), IR, and HRMS spectroscopy. The detection of bisulfite anions was performed through the Michael addition of the bisulfite anion toward the hybrid coumarin-thiazole sensor. The reaction between the sensor and bisulfite anion caused the fluorescence intensity to decrease at 600 nm and to increase at 450 nm and simultaneously yielded a visible color change from purplish red to colorless because the π conjugation between thiazole and coumarin was blocked. The sensor possessed high selectivity and sensitivity for bisulfite with respect to other common anions in aqueous solution. Moreover, the practical value of this sensor was confirmed by its application in the detection of bisulfite anion in human breast adenocarcinoma cells and granulated sugar.