2,7-dichlorofluorescein hydrazide as a new fluorescent probe for mercury quantification: Application to industrial effluents and polluted water samples

A new fluorescent probe 2,7-dichlorofluorescein hydrazide for mercury quantification in aqueous medium has been described. It is based on the spirolactam ring opening of colorless and nonfluorescent 2,7-dichlorofluorescein hydrazide induced by Hg2+ ions through the hydrolytic cleavage of amide bond to produce green-colored highly fluorescent dichlorofluorescein in alkaline medium. The significant color change of this reagent in the presence of mercury ions can be used as a sensitive naked-eye detector. The working range, limit of detection, and relative standard deviations were found to be 0.2-20 ngmL-1, 0.042 ngmL-1, and 0.69 respectively. The proposed method is free from most of the common interfering ions present in the environmental samples. The developed method has been successfully applied to determine trace level mercury from water, soil, and industrial effluents. © 2013 Sureshkumar Kempahanumakkagari et al

Bioimaging of peroxynitrite in MCF-7 Cells by a new fluorescent probe rhodamine b phenyl hydrazide

Peroxynitrite is a potent oxidizing and nitrating agent which has detrimental effects on cells by altering the structure and function of biomolecules present within. A fluorescent probe rhodamine B phenyl hydrazide (RBPH) has been proposed for peroxynitrite (ONOO-) imaging in MCF-7 cells based on its oxidation property, which converts RBPH to pink colored and highly fluorescent rhodamine B. The fluorescence emission intensity of the rhodamine B produced in the above process is linearly related to the concentration of peroxynitrite. The method obeys Beer's law in the concentration range 2-20 nM and the detection limit has been found to be 1.4 nM. The possible reaction mechanism of peroxynitrite with RBPH to produce rhodamine B has been discussed with spectroscopic evidence. The Probe is selective to the peroxynitrite in the pH range 6-8 which is near physiological pH. Fluorescence microscopic studies suggest that the probe is cell permeable and hence peroxynitrite was imaged in MCF-7 cells. © 2013 Springer Science+Business Media New York