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

Synthesis of nickel nitroprusside coordination nanoparticles by simple means: Its characterization and use as electrochemical sensor for sulfide estimation in sewage and water samples Int. J. Electrochem. Sci., 9 (2014) 4692-4708

Nickel nitroprusside (NiNP) complex has been synthesized from two procedures i.e. drop by drop (DbD) and bulk mixing methods. Surface morphology, size and shape of the complex resulted from the two procedures has been compared using scanning electron microscopy (SEM) images. X-ray diffraction (XRD) patterns were used to understand the phase purity and particle size of the complex particles obtained from two procedures. Presence of characteristic functional groups in the complex was examined using IR spectroscopy. From the studies it was clear that, size of the complex particles (n-NiNP) prepared from DbD method was considerably reduced. Carbon paste electrodes (CPEs) were constructed using NiNP complex prepared from DbD and bulk mixing methods to examine their electrocatalytic activity for the oxidation of sulfide. Obviously n-NiNP modified CPE showed enhanced electrocatalytic activity toward the oxidation of sulfide. Attempt has been made to use the nNiNP modified CPE as an electrochemical sensor for sulfide estimation. It showed a linear response over 2 – 14 x10-5 M and 0.2 – 1.4 mM of sulfide. Limit of detection (LOD) and limit of quantification (LOQ) were found to be 0.1 x 10-5 M and 0.43 x10-4 M sulfide respectively for the lower end calibration graph. Interference of various cations and anions generally present along with sulfide in water matrices was studied. Proposed electrochemical sensor has been applied for the estimation of sulfide in sewage and water samples. Good agreement between the results obtained from the proposed electrochemical sensor and standard Methylene blue method was observed