Kiran Kumar Tadi

Bio: Kiran Kumar Tadi is an academic researcher from VIT University. The author has contributed to research in topics: Molecularly imprinted polymer & Ethylene glycol dimethacrylate. The author has an hindex of 13, co-authored 29 publications receiving 406 citations. Previous affiliations of Kiran Kumar Tadi include Visvesvaraya National Institute of Technology & Hebrew University of Jerusalem.

Fluorographene based Ultrasensitive Ammonia Sensor

Abstract: Single molecule detection using graphene can be brought by tuning the interactions via specific dopants. Electrostatic interaction between the most electronegative element fluorine (F) and hydrogen (H) is one of the strong interactions in hydrogen bonding, and here we report the selective binding of ammonia/ammonium with F in fluorographene (FG) resulting to a change in the impedance of the system. Very low limit of detection value of ~0.44 pM with linearity over wide range of concentrations (1 pM–0.1 μM) is achieved using the FG based impedance sensor, andthisscreen printed FG sensor works in both ionized (ammonium) and un-ionized ammonia sensing platforms. The interaction energies of FG and NH3/NH4+ are evaluated using density functional theory calculations and the interactions are mapped. Here FGs with two different amounts of fluorinecontents −~5 atomic% (C39H16F2) and ~24 atomic% (C39H16F12) - are theoretically and experimentally studied for selective, high sensitive and ultra-low level detection of ammonia. Fast responding, high sensitive, large area patternable FG based sensor platform demonstrated here can open new avenues for the development of point-of-care devices and clinical sensors.

Electrochemical Detection of Sulfanilamide Using Pencil Graphite Electrode Based on Molecular Imprinting Technology

Abstract: Molecularly imprinted polymer (MIP) for sulfanilamide (SN) sensing is prepared through in-situ electropolymerization of pyrrole (Py) on pencil graphite electrode (PGE). Computational study using density functional theory with B3LYP level is performed to analyze and evaluate the template-monomer geometry. Among the various functional monomers studied pyrrole is found to have the highest binding interaction energy with SN and it is chosen as a functional monomer. Electropolymerization of pyrrole in the presence of SN on PGE is carried out using cyclic voltammetry. Structural morphology of the imprinted polymer is characterized by field emission scanning electron microscopy (FESEM) studies. Quantitative measurements of MIP based SN detection are performed by using cyclic voltammetry and differential pulse voltammetry studies. Several important kinetic parameters influencing the performance of SN sensor such as limit of detection, linear concentration range and sensitivity etc. are determined and analyzed. Under the optimized conditions, MIP based SN sensor proposed in this work has a very low detection limit of 2.0×10−8 M (S/N=3) and possesses two linear ranges from 5.0×10−8 to 1.1×10−6 M and 1.1×10−6 to 48×10−6 M with a sensitivity value of 1.158 and 0.012 µA/µM respectively. This particular sensor shows a good selectivity towards SN in presence of potential other structural analogue interferences namely sulfamethaxazole, sulfathiazole and sulfadiazine. Furthermore, the fabricated sensor is successfully applied to quantitatively determine and analyze SN present in spiked human serum and ground water samples.

Voltammetric techniques at chemically modified electrodes

Abstract: Voltammetric and amperometric techniques are powerful analytical tools that are widely used in chemical analysis. This article reviews a summary of some important types of modifying agents and their application in voltammetric and amperometric sensors for clinically and biologically important target species reported from the period 2003 to 2013. In this review, different modifiers such as molecularly imprinted polymers (MIPs), polymers, metal complexes, nanomaterials and composite films are discussed. Under the heading of each modifier, method of fabrication, properties, and applications of chemically modified electrodes (CMEs) are given. Tables that give analyte, modified electrode, measurement technique, measuring medium, linear detection range (LDR) and limit of detection (LOD) referenced from original work are also provided.

Covalently Connected Carbon Nanotubes as Electrocatalysts for Hydrogen Evolution Reaction through Band Engineering

Abstract: Controlled assembly of mesoscopic structures can bring interesting phenomena because of their interfaces. Here, carbon nanotubes (CNTs) are cross-coupled via a C–C bonding through Suzuki reaction resulting in three-dimensional (3D) CNT sponges, and these 3D CNTs are studied for their efficacy toward the electrocatalytic hydrogen evolution reaction (HER) in acidic medium—one of the promising methods for the production of a renewable energy source, hydrogen. Both single and multiwall CNTs (SWCNTs and MWCNTs) are studied for the development of 3DSWCNTs and 3DMWCNTs, and these 3D CNTs are found to be HER active with small reaction onset potentials and low charge-transfer resistances unlike their uncoupled counterparts. First-principle density functional calculations show that the combination of electron acceptor and donor bonded to the CNT network can provide a unique band structure modulation in the system facilitating the HER reaction. This study can provide possibilities for band engineering of CNTs via fu...

经Co

Abstract: Poly (ionic liquid)s attracted enormous attention as adsorbents for the CO2 separation from natural gas. Hence, in this work poly (1-butyl-3-vinylimidazolium bromide), P[VBIm][Br], poly (1-butyl-3-vinylimidazolium thiocyanate), P[VBIm][SCN], and poly (1-butyl-3-vinylimidazolium tetrafluoroborate), P[VBIm][BF4] were synthesized and evaluated their CO2 adsorption performance. The synthesized poly(ionic liquid)s were characterized by 1H NMR, FT-IR spectroscopy, and differential scanning calorimetery (DSC) analysis. The CO2 adsorption was studied at various temperatures and pressures by quartz crystal microbalance (QCM) and experimental data were correlated by a model of dual-mode. The Henry and Langmuir contributions in CO2 adsorption were evaluated. The obtained thermodynamics and kinetics parameters of CO2 adsorption reveal that CO2 adsorption has an exothermic and physisorption nature. Also, density functional theory (DFT) computations were done in order to assess interactions between poly(ionic liquid)s with CO2 gas. DFT computations corroborated that interaction of P[VBIm][SCN] with CO2 is stronger than those of other poly(ionic liquid)s.

Sensing at the Surface of Graphene Field-Effect Transistors

Abstract: Recent research trends now offer new opportunities for developing the next generations of label‐free biochemical sensors using graphene and other two‐dimensional materials. While the physics of graphene transistors operated in electrolyte is well grounded, important chemical challenges still remain to be addressed, namely the impact of the chemical functionalizations of graphene on the key electrical parameters and the sensing performances. In fact, graphene – at least ideal graphene – is highly chemically inert. The functionalizations and chemical alterations of the graphene surface – both covalently and non‐covalently – are crucial steps that define the sensitivity of graphene. The presence, reactivity, adsorption of gas and ions, proteins, DNA, cells and tissues on graphene have been successfully monitored with graphene. This review aims to unify most of the work done so far on biochemical sensing at the surface of a (chemically functionalized) graphene field‐effect transistor and the challenges that lie ahead. The authors are convinced that graphene biochemical sensors hold great promise to meet the ever‐increasing demand for sensitivity, especially looking at the recent progresses suggesting that the obstacle of Debye screening can be overcome.