Browsing by Author "Surbhi Sharma"

Now showing 1 - 10 of 10

2-Dimensional Magnesium Oxide/Polyaniline Nanocomposite Modified Glassy Carbon Electrode for Electrochemical Detection of Dopamine and 4-Nitrophenol
(John Wiley and Sons Inc, 2024) Ashish Kumar; Surbhi Sharma; Chandra Shekhar Pati Tripathi; Debanjan Guin
In this study, we have developed an electrochemical sensor based on a polyaniline (PANI) integrated magnesium oxide nanosheet (MgO-NSs) modified glassy carbon electrode (GCE) for the rapid electrochemical detection of dopamine (DA) and 4-nitrophenol (4-NP). 2-D MgO-NSs were synthesized using a straightforward one-step sugar-blowing method, and PANI was synthesized by the oxidative polymerization of aniline. The nanocomposite (PANI-MgO) was prepared by simple mechanical blending of MgO-NSs with PANI. The as-synthesized nanocomposites were characterized using several analytical techniques to determine their morphological and microstructural properties. The as-synthesized PANI, MgO, and PANI-MgO were further electrochemically characterized using Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS) techniques. The fabricated PANI-MgO/GCE showed a considerable increase in the redox peak currents of DA and 4-NP, suggesting that PANI-MgO/GCE substantially enhances the electrocatalytic oxidation of DA and the reduction of 4-NP. The analytical performance of PANI-MgO/GCE for the detection of DA and 4-NP was investigated using Differential Pulse Voltammetry (DPV). The developed sensor was successfully applied for the detection of DA and 4-NP in real samples with good recovery results. © 2024 Wiley-VCH GmbH.
Barium Titanate Nanocubes as a Dual Electrochemical Sensor for Detection of Dopamine and Acetaminophen
(Institute of Physics, 2022) Mohd Ali; Surbhi Sharma; Renuka Singh; Keshav Sharma; Shukla Majhi; Debanjan Guin; Chandra Shekhar Pati Tripathi
In the present work, we report on the development of a highly sensitive electrochemical sensor for the rapid detection of dopamine, and acetaminophen molecules based on barium titanate nanocubes deposited on a glassy carbon electrode. The as-synthesized barium titanate nanocubes were characterized using X-ray diffraction measurements, field emission scanning electron microscopy, and UV-vis diffuse reflectance spectroscopy. The electrochemical performances of the as synthesised nanomaterials were investigated by cyclic voltammetry and differential pulse voltammetry. A linear response was exhibited by the modified electrode for both dopamine, and acetaminophen in the range 10-100 μM, and the detection limit (S/N=3) was calculated to be 0.35 μM, 0.23 μM respectively. Under the optimised conditions, highly stable, sensitive, selective, and reproducible performances were exhibited by the electrochemical sensor. Furthermore, the as developed sensor also showed acceptable recoveries for the analysis of real samples. © 2022 The Electrochemical Society ("ECS"). Published on behalf of ECS by IOP Publishing Limited.
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.
Covalent functionalization of graphene oxide with l-lysine for highly sensitive and selective simultaneous electrochemical detection of rifampicin and acetaminophen
(Springer Science and Business Media B.V., 2024) Keshav Sharma; Ashish Kumar; Surbhi Sharma; Chandra Shekhar Pati Tripathi; Debanjan Guin
In the present work, graphene oxide covalently functionalized with l-lysine (LSN@GO)-based electrochemical sensor has been developed for the ultrasensitive individual as well as the first ever simultaneous detection of Rifampicin (RIFA) and Acetaminophen (APAP) drugs. The synthesized LSN@GO composite, as well as its precursors LSN and GO, were characterized using FT-IR, XRD, TGA, XPS, SEM and EDAX. The electrochemical studies were performed using Cyclic Voltammetry (CV), Linear Sweep Voltammetry (LSV), and Electrochemical Impedance Spectroscopy (EIS). The fabricated LSN@GO/GCE electro-sensor’s interface exhibited efficient electrical activity for the analysis of RIFA and APAP under the optimized conditions, owing to its substantial electrochemically active surface area and exceptional electron transport capabilities. The detection of RIFA and APAP in various pH environments entailed a proton-dependent mechanistic approach. The sensor displayed a robust linear correlation over a broad range (0.5 to 10 µM) for both RIFA and APAP, with low detection limits of 4.3 nM for RIFA and 5.8 nM for APAP (S/N = 3), along with quantification limits of 14.6 nM for RIFA and 19.4 nM for APAP (S/N = 10) for their individual detection. For simultaneous detection, the detection limit of 4.2 nM for RIFA and 6.0 nM for APAP were observed. We successfully detected spiked RIFA and APAP in real drug and urine samples without pre-treatment, demonstrating significant detection limits and no notable interference from excipients with satisfactory recovery data. The developed sensing platform demonstrated exceptional electrochemical performance for the detection of RIFA and APAP, showcasing significant potential for applications in clinical diagnosis and pharmaceuticals. Graphical abstract: (Figure presented.) © The Author(s), under exclusive licence to Springer Nature B.V. 2023.
Fabrication of a non-enzymatic electrochemical sensor based on magnesium oxide nanosheets for selective and sensitive detection of hydrogen peroxide in food samples
(Springer Science and Business Media B.V., 2024) Surbhi Sharma; Keshav Sharma; Ashish Kumar; Chandra Shekhar Pati Tripathi; Debanjan Guin
A novel enzyme-free sensor, constructed on a glassy carbon electrode (GCE) and featuring 2-dimensional (2-D) nanoporous magnesium oxide nanosheets (MgO-NSs), has been fabricated to enable the highly sensitive and selective detection of hydrogen peroxide (H2O2). MgO-NSs were successfully synthesized through a single-step, non-hazardous, and cost-effective sugar-blowing technique. The microstructure, porosity, thermal stability, and morphology of MgO-NSs were analyzed under XRD, FT-IR, FESEM, HR-TEM, TGA, and BET surface area. The electrochemical properties of MgO-NSs modified glassy carbon electrode (GCE) (MgO-NSs/GCE) were probed toward H2O2 sensing using CV, DPV, EIS, and amperometry techniques at varying concentrations, pH of the solution, and different scan rates. The fabricated electrode displayed remarkable selectivity, high sensitivity, and a linear response toward H2O2 in a wide concentration range of 20 µM-1000 µM at neutral pH with 0.224 µM limit of detection (LOD) and 0.753 µM limit of quantification (LOQ). The proposed electrochemical sensor based on MgO-NSs/GCE demonstrates multiple advantages like exceptionally high sensitivity, high selectivity, great stability, reproducibility, and excellent response toward the detection of hydrogen peroxide in milk and mixed-fruit juice samples as compared to the reports available in the literature. Graphical abstract: (Figure presented.). © The Author(s), under exclusive licence to Springer Nature B.V. 2023.
Facile synthesis of Ag NPs@MgO nanosheets for quantitative SERS-based detection and removal of hazardous organic pollutants
(Elsevier B.V., 2024) Surbhi Sharma; Keshav Sharma; Shukla Majhi; Chandra Shekhar Pati Tripathi; Debanjan Guin
Surface-enhanced Raman spectroscopy (SERS) is a highly precise and non-invasive analytical method known for its ability to detect vibrational signatures of minute analytes with exceptional sensitivity. However, the efficacy of SERS is subject to substrate properties, and current methodologies face challenges in attaining consistent, replicable, and stable substrates to regulate plasma hot spots across a wide spectral range. This study introduces a straightforward and economical approach that incorporates monodispersed silver nanoparticles onto 2-D porous magnesium oxide nanosheets (Ag@MgO-NSs) through an in-situ process. The resulting nanocomposite, Ag@MgO-NSs, demonstrates substantial SERS enhancement owing to its distinctive plasmonic resonance. The effectiveness of this nanocomposite is exemplified by depositing diverse environmental pollutants as analytes, such as antibiotic ciprofloxacin (CIP), organic dyes like rhodamine 6G (R6G) and methylene blue (MB), and nitrogen-rich pollutant like melamine (MLN), onto the proposed substrate. The proposed nanocomposite features a 2-D porous structure, resulting in a larger surface area and consequently providing numerous adsorption sites for analytes. Moreover, engineering the active sites of the nanocomposite results in a higher number of hotspots, leading to an enhanced performance. The nanocomposite outperforms, exhibiting superior detection capabilities for R6G, MB, and MLN at concentrations of 10-6 M and CIP at concentration of 10-5 M, with impressive uniformity, reproducibility, stability, and analytical enhancement factors (EF) of 6.3 x 104, 2 x 104, 2.73 x 104 and 1.8 x 104 respectively. This approach provides a direct and cost-effective method for the detection of a broad spectrum of environmental pollutants and food additives, presenting potential applications across diverse domains. The detected environmental pollutants and food additives are removed through both catalytic degradation (R6G and MB) and adsorption (CIP and MLN). © 2024 Elsevier B.V.
Gum Arabic-mediated synthesis of silver nanoparticles for their applications as colorimetric and SERS-based detection of hydrogen peroxide
(Springer, 2024) Shukla Majhi; Ashish Kumar; Surbhi Sharma; Chandra Shekhar Pati Tripathi; Debanjan Guin
Abstract: We report on the one-step green method to synthesize Gum Arabic stabilized silver nanoparticles (GA-Ag NPs). The synthesized particles are monodispersed and in the size range of 15–20 nm. The synthesized Ag NPs are used as a colorimetric sensor for the detection of H2O2 and glucose with a detection limit of 11.7 nM and 0.13 µM, respectively. The sensor has also been used for the detection of H2O2 in water samples and glucose in human blood serum samples. The GA-Ag NPs decorated on filter paper have also shown excellent SERS activity for the detection of H2O2 with a detection limit of 0.56 µM. Graphical abstract: (Figure presented.) © The Author(s), under exclusive licence to The Japan Society for Analytical Chemistry 2023. Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
Magnetically separable Ag@Fe3O4-GO nanocomposites for SERS detection, removal of organic pollutants and oil from water, and antibacterial applications
(Royal Society of Chemistry, 2024) Keshav Sharma; Shukla Majhi; Renuka Singh; Surbhi Sharma; Priya Dhyani; Chhaya Goyal; Chandra Shekhar Pati Tripathi; Debanjan Guin
A facile wet chemical method was employed to synthesize magnetically separable Ag@Fe3O4-GO nanocomposites (NCs). The synthesized Ag@Fe3O4-GO NCs were characterized by different analytical techniques including X-ray diffraction (XRD), Raman, vibrating sample magnetometer (VSM), Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In the synthesized Ag@Fe3O4-GO NCs, the role of GO is to adsorb organic dyes from wastewater, superparamagnetic Fe3O4 nanoparticles (NPs) assist magnetic separation, and Ag NPs act as a SERS substrate for the detection of organic dyes and as a catalyst to reduce organic pollutants in the presence of a reducing agent (NaBH4). The catalytic efficiency of the synthesized Ag@Fe3O4-GO NCs was evaluated in the reduction of organic pollutants such as methylene blue (MB) in water under mild conditions. These nanocomposites are also efficient for the removal of lubricant oil from water by applying a simple external magnetic field. The composite also displays antibacterial activity towards Gram-positive and Gram-negative bacteria. © 2024 The Royal Society of Chemistry.
Nano-engineered polyester fabric based on silver nanoparticles loaded L-lysine-grafted graphene oxide for catalytic degradation and SERS detection of industrial pollutants
(Elsevier B.V., 2024) Keshav Sharma; Renuka Singh; Surbhi Sharma; Chandra Shekhar Pati Tripathi; Debanjan Guin
We report on the surface modification of low-cost flexible polyester fabric (PEF) cloth through the assembly of hydrophilic silver nanoparticles (Ag NPs) on L-Lysine (LYS) functionalized graphene oxide (GO) (Ag@LYS-GO@PEF), tailored for integrated applications in catalysis and surface-enhanced Raman scattering (SERS) for reduction and sensing of eight industrial water pollutants. Further, the Ag@LYS-GO@PEF substrate has been employed as a catalytic platform for the sodium borohydride-based reduction of various nitrophenols, namely 4-nitrophenol, 2-nitrophenol, 2,4,6-trinitrophenol, as well as methyl orange and methyl red dyes, with high stability and reproducibility, with pseudo-first-order rate constant values determined to be 5.4 × 10−3 s−1, 4.2 × 10−3 s−1, 1.4 × 10−3 s−1, 1.9 × 10−3 s−1, and 3.0 × 10−3 s−1, respectively. Additionally, the Ag@LYS-GO@PEF substrate served as a remarkably sensitive and flexible platform for SERS, enabling the detection of organic dyes like rhodamine B, rhodamine 6G, and methylene blue, with enhancement factors (EF) of 3.0 × 104, 2.4 × 103, and 7.5 × 103, respectively. Moreover, our fabrication approach offers a straightforward pathway to cost-effective functional substrates based on polyester fabric cloth, catering to a range of multichannel applications. © 2024 Elsevier B.V.
Silver nanoparticles decorated on graphene oxide modified polyester fabric: Catalytic reduction of 4-nitrophenol, organic dyes and SERS application
(Elsevier Ltd, 2022) Keshav Sharma; Mohd Ali; Renuka Singh; Shukla Majhi; Surbhi Sharma; Chandra Shekhar Pati Tripathi; Debanjan Guin
We report on the immobilization of silver nanoparticles on functional graphene oxide modified polyester fabric (AgNPs@GO/PET) for catalytic reduction of organic pollutants. In this work, the polyester fabric was modified with hydrophobic graphene nanosheets using a simple dip-coating method. The as prepared hydrophobic inert graphene oxide modified polyester fabric (GO/PET) substrate was used to stabilize oleylamine coated monodispersed silver nanoparticles. The morphology, size, and structure of the catalyst was investigated through X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), dynamic light scattering (DLS), Fourier-transform infrared spectroscopy (FTIR), Thermogravimetric analysis (TGA) and Raman spectroscopy. Outstanding catalytic performance was exhibited by the AgNPs@GO/PET catalyst for the reduction reaction of 4-nitrophenol, methyl orange and methyl red. Surface enhanced Raman scattering (SERS) was also employed for the time dependent monitoring of reduction of 4-Nitrothiophenol. The present work highlights the importance of the as developed catalyst for the catalytic reduction of organic pollutants and SERS sensing with excellent stability and reusability. © 2022 Elsevier Ltd