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    Ionic liquid based high performance electrochemical sensor for ascorbic acid in various foods and pharmaceuticals
    (Elsevier, 2016-07-18) Kumar, Bhajanthri Natesh; Arumugam, Vasanthakumar; Chokkareddy, R.; Redhi, Gan G.
    In the present study, 1-butyl-3-methyl imidazolium tetra fluoroborate ionic liquid (IL), boron nitride (BN) and magnetite nanoparticles (Fe3O4NPs) based nanocomposite (IL-BN-Fe3O4NPs) was successfully synthesised and used to fabricate glassy carbon electrode (GCE) for the determination of ascorbic acid (AA). The nanocomposite was characterized by Fourier transformation infrared spectroscopy (FTIR), x-ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM), electron diffraction spectroscopy (EDS) and transmission electron micros-copy (TEM) techniques to observe the surface morphology. Cyclic voltammetry (CV) was performed to assess the electrochemical performance of IL-BN-Fe3O4NPs/GCE towards ascorbic acid (AA) in 0.1 M phosphate buffer solu-tion (PBS) at pH 7. The CV results obtained reveal that the significant enhancement of anodic peak current with increased sensitivity and conductivity. The differential pulse voltammetric results obtained indicates the linear increment of electrochemical signals with an increase in the concentration of AA in the range of 1–12 μM. Based on the calibration plot, limit of detection and limit of quantification were calculated and found to be 0.042 and 0.139 μM respectively. The electrochemical sensor showed outstanding sensitivity, selectivity, repeat-ability and stability. In addition to this IL-BN-Fe3O4NPs/GCE sensor was practically applied for the routine analysis of AA in various food and pharmaceutical samples.
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    Fabrication of copper nanoparticles decorated multiwalled carbon nanotubes as a high performance electrochemical sensor for the detection of neotame
    (Elsevier, 2015) Bathinapatla, Ayyappa; Kanchi, Suvardhan; Singh, Parvesh; Sabela, Myalowenkosi Innocent; Bisetty, Krishna
    A highly sensitive and novel electrochemical sensor for the detection of neotame using differential pulse voltammetry with a modified glassy carbon electrode is presented. The method was further customized by the fabrication of the electrode surface with copper nanoparticles–ammonium piperidine dithiocar-bamate–mutiwalled carbon nanotubes assimilated with β-cyclodextrin. The multiwalled carbon nano-tubes assimilated with β-cyclodextrin/glassy carbon electrode exhibited catalytic activity towards the oxidation of neotame at a potential of 1.3 V at pH 3.0. The transmission electron microscopy, thermogravimetric analysis, frontier transform infrared spectroscopy and cyclic voltammetry were employed to characterize the electrochemical sensor. The sensitivity and detection limits of the electrode increased two-fold in contrast to the β-CD-MWCNTs/GCE sensor. The developed method was successfully applied for the determination of neotame in food samples, with results similar to those achieved by our modified capillary electrophoresis method with a 96% confidence level.