Enzyme Based Electrochemical Biosensor for Ethanolamine

Enzyme based electrochemical detection method developed for chemical toxicant ethanolamine (EA). Monoamine oxidase A (MAO‐A) enzyme was used for the oxidation of EA. A direct electron transfer from the electrode to EA without any mediator with the help of MAO‐A enzyme was attained and this confirms the application of this methodology for the development of third generation biosensor for EA sensing well below the IDLH (30 ppm) value of EA. Moreover, heterogeneous rate constant (0.021s^?1) and the number of electron involved (5.2) were deduced for EA in PBS buffer. The calibration plot showed linearity 2.02×10^?4 M to 10.10×10^?4 M of EA in PBS buffer with detection limit 4.1 ppm. The modified electrodes are characterized by Raman and Electrochemical impedance spectroscopy (EIS) techniques. The outcome of this work indicates about the utility of this methodology for the sensing of EA in the environment if it is present as well as to degrade EA into other compounds without using any indicator or mediator.     

Synthesis of poly(N-vinyl-2-pyrrolidone) adsorbed-AuPt/C bimetallic nanoparticles and their unusual electrocatalytic activity towards methanol tolerant oxygen reduction reaction

Journal of Solid State Electrochemistry - It has been suggested that the presence of adsorbed impurities, such as capping agent or organic reaction products adsorbed on the metallic nanoparticles,...     

Cone calorimeter analysis of flame retardant poly (methyl methacrylate)-silica nanocomposites

Nanocomposite is a promising method to reduce fire hazards of polymers. Specifically due to increased interfacial area between polymer and nanofillers, polymer nanocomposites have an advantage in reducing fire hazards efficiently even when the flame retardant additives are at a concentration of 5 mass% or less. In theory, crosslinking between the polymer chains can create a carbon-dense structure to enhance char formation, which can further promote the flame retardancy. However, little research has been done to explore the flammability of crosslinking polymer nanocomposites with a low concentration of nanosilica particles. In this study, crosslinked and non-crosslinked poly (methyl methacrylate) (PMMA) nanocomposites of a low concentration of nanosilica particles have been prepared via an in situ method. Their fire properties were tested by using the cone calorimeter at the heat flux of 50 kW m^?2. Although silica-containing flame retardants tend to negatively affect the ignitability and soot production especially at a high concentration, through the condensed phase mechanism, the samples of high loading rate of nanosilica particles show better fire retardancy performance in the aspect of flammability, including decreased heat release rate, mass loss rate, and total heat release. Additionally, crosslinking indeed attributes to the less intensive combustion of crosslinked PMMA samples, especially at a low concentration of nanosilica. The combination of nanosilica particles with the modification of the internal structure of the polymer nanocomposites might be a good strategy to improve fire retardancy.     

Biocidal and catalytic efficiency of ruthenium(III) complexes with tridentate Schiff base ligands

The reaction of the Schiff bases (obtained by condensing isatin with o‐aminophenol/o‐aminothiophenol/o‐aminobenzoic acid) with [RuX₃(EPh₃)₃] (where X = Cl/Br; E = P/As) in benzene afforded new, air‐stable Ru(III) complexes of the general formula [Ru(L)X(EPh₃)₂] (L = dianion of tridentate Schiff bases). In all these reactions, the Schiff base ligand replaces one triphenylphosphine/triphenylarsine and two chlorides/bromides from the ruthenium precursors. The complexes were characterized by elemental analyses, spectral (FT–IR, UV–vis, ¹H and ¹³C NMR for the ligands, and EPR) and electrochemical studies. All the metal complexes exhibit characteristic LMCT absorption bands in the visible region. The catalytic reactivity proved these complexes to be efficient catalysts in the oxidation of alcohols and C? C coupling. All the complexes were screened for their biocidal efficiency against bacteria such as Staphylococcus epidermidis and Escherichia coli and fungi such as Botrytis cinerea and Aspergillus niger at 0.25, 0.50 and 1% concentrations. Copyright © 2010 John Wiley & Sons, Ltd.     

Europium removal with a mineral mixtre

Natural mixture containing mostly minerals of iron, sillicon, magnesium, aluminium and calcium was exploited for the decontamination study of europium radionuclides from aqueous radioactive waste solutions. The physicochemical conditions, such as shaking and equilibration time, nature of hydrogen ions, pH, temperature, concentrations of adsorbate and adsorbent were experimentally determined. This study showed quantitative adsorption beyond pH 7 and under optimized conditions, up to 33 g of the adsorbate can be rapidly removed from radioactive effluents using only 1 kg of the mineral mixture (MM). Desorption study of the solidified radioactive waste product reveals no significant loss (< 0.01% month), indicating MM as an effective material for removal of radioactive europium and storing it in solid form over a long period of time.     

Mass spectrometry—II: The unimolecular decomposition of benzaldehyde azine in the gas phase induced by electron-impact

The mass spectra of benzaldehyde azine-α, αA-d² (III) and benzaldehyde azine-d¹⁰ (IV) reveal that both ring and α hydrogen are lost from the molecular ion of benzaldehyde azine (II) in forming the [M –1] ion. Data from the spectra of III and IV at 70 eV and reduced ionizing voltages are consistent with the existence of two competing pathways producing [M –1] ions. Rearrangement ions are observed in the spectra of II. Randomization is unimportant in the electron-impact-induced fragmentation reactions of II. The rearrangement-fragmentation reactions for II in general parallel those previously observed for acetophenone azine (I).     

Concentration and distribution of toxic elements in rice and husk

Five varieties of rice have been analyzed to study the prevailing concentration and distribution of 10 trace elements in rice and rice husk. NAA in combination with AAS has been utilized for the determination of Hg, Pb, Cd, As, Br, Sb, Se, Ni, Al and Cs. The elemental ratios of rice to husk and within rice have been calculated to get information regarding their uptake channels. The daily supply of the elements to the human body has been estimated and from these the safety of the diet has been assessed by comparing with the suggested tolerance levels. A global distribution pattern of some of these elements in rice has also been evaluated.     

Pd–Co alloy as an efficient recyclable catalyst for the reduction of hazardous 4-nitrophenol

Research on Chemical Intermediates - Palladium–Cobalt (Pd–Co) alloys with different atomic ratios were synthesized successfully by borohydride-assisted chemical reduction method....     

Acid catalysis in the N-bromosuccinimide-propargyl alcohol reaction

The reaction of N-bromosuccinimide (NBS) with propargyl alcohol in aqueous acidic medium is hydroxybromination. It is first order with respect to NBS, propargyl alcohol and H⁺, and inverse first order with respect to succinimide. The kinetic results point to solvated bromonium ion as the reactive species.