Browsing by Author "Deepika Choudhary"

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BSA stabilized copper nanoclusters as a highly sensitive and selective probe for fluorescence sensing of Fe3+ ions
(Elsevier B.V., 2022) Renuka Singh; Shukla Majhi; Keshav Sharma; Mohd Ali; Surbhi Sharma; Deepika Choudhary; Chandra Shekhar Pati Tripathi; Debanjan Guin
We report on the green synthesis of an effective fluorescent based sensor for selective, sensitive and rapid detection of Fe3+ ions using bovine serum albumin (BSA) stabilized copper nanoclusters. The fluorescence intensity of the BSA-CuNCs has been found to be quenched with the addition of Fe3+ ions. An extremely high selectivity and low detection limit of 10 nM (3σ/k) was observed. The sensor was also employed for the sensing of Fe3+ in wastewater and human blood serum samples. The features exhibited by the fluorescent probe suggest its promising applications in the area of analytical and biological field. © 2021 Elsevier B.V.
Photocatalytic degradation of rhodamine B and methylene blue dyes using tungsten oxide/barium titanate nanocomposite
(Springer, 2025) Richa Kumari; Naman Chandrakar; Deepika Choudhary; Debanjan Guin; Chandra Shekhar Pati Tripathi
Photocatalysis has emerged as a significant approach for tackling environmental challenges, particularly in removing dye pollutants from water. However, a major obstacle to enhancing the efficiency of photocatalysts is the fast recombination of charge carriers, which hampers the degradation of pollutants. Here, we present a novel hybrid photocatalyst composed of BaTiO3 nanoparticles and WO3 nanorods, designed to enhance the dye degradation in visible light. Our study shows that the sample with 5.0 wt% BaTiO3 (W/BT5) demonstrates significantly better performance than pure WO3, BaTiO3, and all other composites. W/BT5 enhances the degradation of rhodamine B (RhB) by 1.25 times and methylene blue (MB) by 1.38 times compared to WO3 alone. This improvement is attributed to the well-aligned band structures, which promote effective separation and movement of the photogenerated charge carriers. Our findings introduce a new strategy for boosting the activity of photocatalysts through hybrid composites, paving the way for more efficient environmental remediation technologies. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2025.
Thiol terminated chitosan capped silver nanoparticles for sensitive and selective detection of mercury (II) ions in water
(Elsevier B.V., 2018) Pinki Sharma; Mohini Mourya; Deepika Choudhary; Manoj Goswami; Indra Kundu; Mahabeer Prasad Dobhal; Chandra Shekhar Pati Tripathi; Debanjan Guin
In this paper, we report a simple method for the optical detection of environmentally toxic mercury (II) ions (Hg2+) in water using chitosan capped silver nanoparticles (Ch-Ag NPs). The yellow colored aqueous solution of Ch-Ag NPs instantly (10 s) became colorless with addition of Hg2+ ions. Cu2+, and Fe3+ ions also produced colorless solution after 1 min. To overcome the Cu2+ and Fe3+ interference, thiol terminated chitosan was synthesized via amide coupling formation between amine group of chitosan and carboxylic acid group of 3-Mercaptopropanoic acid (3-MPA). The detailed study of selectivity, sensitivity, effect of interfering radicals, and response time confirmed that thiol terminated chitosan capped silver nanoparticles (Mod-Ch-Ag NPs) are highly selective and speedy for Hg2+ ions detection. The limit of detection was found to be 5 ppb. Furthermore, since the change in color with addition of mercury can be observed by naked eye, the developed nanosensor can also be utilized for real field applications. Hydrogel of Mod-Ch-Ag NPs was successfully synthesized and it was also found highly specific for Hg2+ ions. It was observed that separation of Hg2+ ions is also possible by simply changing the pH of the solution containing colorless Hg2+ with Mod-Ch-Ag NPs. © 2018 Elsevier B.V.
Wittig Ylide Mediated Decomposition of N -Sulfonylhydrazones to Sulfinates
(American Chemical Society, 2018) Deepika Choudhary; Vineeta Khatri; Ashok K. Basak
N-Sulfonylhydrazones generate sulfinates selectively when treated with a stabilized Wittig ylide in a polar aprotic solvent at elevated temperature. The transition metal and base free decomposition method is applicable to N-sulfonylhydrazones generated from a number of aromatic and heteroaromatic aldehydes and ketones. In the case of N-tosylhydrazones derived from O-allyl and O-propargyl salicylaldehydes, selective formation of sulfinate occurs over intramolecular [3 + 2]-cycloaddition reaction. © 2018 American Chemical Society.