http://nopr.niscair.res.in/handle/123456789/797 Search the Channel search http://nopr.niscair.res.in/simple-search http://nopr.niscair.res.in/handle/123456789/1213 Title: Micellar effects on the electrochemical oxidation of norepinephrine and its determination in the presence of ascorbic acid <br/> <br/>Authors: Li, Yan; Wen, Xiao-Lin; Liu, Zhong-Li <br/> <br/>Abstract: The electrochemistry of norepinephrine has been studied by cyclic voltammetry at glassy carbon electrode in the presence of cetyltrimethylammonium bromide and sodium dodecyl sulfate micelles at different pHs. The anodic peak potential and peak current are found to be dependent on the charge and the concentration of the surfactants. The anodic peak potential and peak current change abruptly around the CMC of the surfactants and reach a plateau above the CMC. The anodic peak potential shifts to more positive values in CTAB and to more negative values in SDS. The electrocatalytic oxidation of norepinephrine in the presence of ascorbic acid in SDS micellar solution enables a sensitive determination of norepinephrine in the presence of ascorbic acid. <br/> <br/>Page(s): 962-965 http://nopr.niscair.res.in/handle/123456789/1212 Title: Simultaneous determination of ascorbic acid, dopamine and uric acid using PEDOT polymer modified electrodes <br/> <br/>Authors: Jeyalakshmi, S Radha; Kumar, S Senthil; Mathiyarasu, J; Phani, K L N; Yegnaraman, V <br/> <br/>Abstract: Dopamine, uric acid and ascorbic acid have been determined simultaneously on a poly(3,4-ethylenedioxythiophene) modified electrode using electrochemical techniques. On a bare glassy car-bon electrode, all three undergo oxidation and appear as a single peak at around 200 mV, whereas on the modified electrode, dis-tinct peaks with clear potential separation are observed, paving way for their simultaneous determination. Detection limits of 7.4 μM, 1.2 M and 1.4 μM for ascorbic acid, dopamine and uric acid, respectively are observed by pulse voltammetry. The possible interference from creatinine, norepinephrine, epinephrine, glu-cose, ascorbic acid, urea, oxalate and acetylsalicylic acid (aspirin) has been tested. The protocol developed using this modified glassy carbon electrode has been evaluated using the human blood serum samples for the simultaneous determination of dopamine and uric acid. <br/> <br/>Page(s): 957-961 http://nopr.niscair.res.in/handle/123456789/1211 Title: Kinetics of reduction of [Co(NH₃)₅N₃]Cl₂ by iron (II) in CTAB/n-heptane/butanol/water reverse micelles <br/> <br/>Authors: Majumdar, Tapas; Mahapatra, Ambikesh <br/> <br/>Abstract: The kinetic study of reduction of pentaammineazidocobalt(III) chloride complex by Mohr’s salt (ammonium ferrous sulphate) has been carried out in the water pools of cationic reverse micelles of cetyltrimethylammonium bromide (CTAB). The reaction is first order each in Co(III) complex and iron(II) in all water-to-surfactant molar ratios, i.e. at all W values. The observed pseudo first order rate constant (kobs) versus W plot shows highest rate at W = 8.33. The kinetics has been accounted for by a mechanism involving bimolecular azido-bridged inner-sphere intermediate complex formation between Co(III) complex and iron(II). The significant increase of rate in reverse micellar media as compared to that in aqueous medium is due to the lower micropolarity of the water pool and bound state of reactants in this reverse micellar media, both facilitating the intermediate formation. The activation parameters (standard enthalpy of activation, Δ‡Hº and standard entropy of activation, Δ‡Sº) of the reaction at different W values have been calculated which corroborate the kinetics of the reaction. <br/> <br/>Page(s): 952-956 http://nopr.niscair.res.in/handle/123456789/1210 Title: Low-temperature heat capacity and standard molar enthalpy of formation of crystalline (S)–(+)–Ibuprofen (C₁₃H₁₈O₂)(s) <br/> <br/>Authors: Di, You-Ying; Ye, Chun-Tian; Tan, Zhi-Cheng; Zhang, Guo-Ding <br/> <br/>Abstract: Low-temperature heat capacities of the compound,(S)–(+)–Ibuprofen (C₁₃H₁₈O₂), have been measured by a precision automated adiabatic calorimeter in the temperature range 78 – 348 K. The experimental molar heat capacities in the temperature range 78 – 345 K have been fitted to a polynomial equation. The smoothed heat capacities and thermodynamic functions, (HT - H₂₉₈․₁₅ĸ) and (ST - S₂₉₈․₁₅ĸ), of the compound have been calculated by the heat-capacity polynomial equation. The constant-volume energy of combustion of the compound, has been found to be ΔUc (C₁₃H₁₈O₂, s) = – (7136.94 ± 4.74) kJmol⁻¹ by means of a home-made oxygen-bomb combustion calorimeter at T = 298.15 ± 0.001 K. The standard molar enthalpy of combustion of the sample has been calculated to be ΔcHmº (C₁₃H₁₈O₂, s) = – (7145.62 ± 4.74) kJmol⁻¹, from the constant-volume combustion energy. The standard molar enthalpy of formation of the compound has been derived, ΔքHmº (C₁₃H₁₈O₂, s) = – (542.48 ± 5.05) kJmol⁻¹, from the combination of the data of standard molar enthalpy of combustion of the compound with other auxiliary thermodynamic quantities through a Hess thermochemical cycle. <br/> <br/>Page(s): 947-951