Indian Journal of Chemistry

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Sect. A: Inorganic, Bio-inorganic, Physical, Theoretical & Analytical

 

VOLUME 46A

NUMBER 6

JUNE 2007

 

CONTENTS

 

 

895

 

DFT studies on anionic hetero atom (N or/and S) substitution in TiO2

 

 

 

 

 

 

 

 

M Sathish, M Sankaran, B Viswanathan* &
R P Viswanath

 

 

 

The variation in the band structure, band gap and stability of N/S substituted TiO2 have been studied. The study shows that band gap reduction in TiO2 may be achieved by substitutional doping of TiO2 with non-metallic hetero atoms like N and S. The magnitude of band gap reduction increases with decrease in the electronegativity difference between Ti and the hetero atom. Also, on S doping the oxygen atoms are replaced in preference to the Ti atoms.

 

 

899

 

Stereochemical configuration of poly(2-hydroxyethyl - methacrylate) by NMR spectroscopy

 

 

 

 

 

 

 

 

 

 

Sunita Hooda* & Ashok Kumar Goyal

 

 

 

Poly(2-hydroxyethyl methacrylate) has been prepared by free radical bulk polymerization at 80°C and its microstructure characterized by one-dimensional (1H, 13C{1H}) and two-dimensional (HSQC, TOCSY and HMBC) NMR spectra. The methyl, methylene and carbonyl carbon resonance signals are sensitive to various configurational sequences. 2D HMBC spectrum shows long range coupling between quaternary, methylene and carbonyl carbon with methyl protons.

 

 

904

 

DNA interactions of mixed ligand copper(II) complexes with sulphur containing ligands

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

P Murali Krishna, K Hussain Reddy*,
Pitchika G Krishna & G H Philip

 

 

 

Mixed ligand copper(II) complexes having the composition [Cu(tsc)Cl2], [Cu(tsc)2Cl2], [Cu(phen)Cl2], [Cu(dmso)2Cl2], [Cu(phen)(tsc)Cl2] and [Cu(dmso)2(tsc)Cl2] have been synthesized and characterized on the basis of elemental analyses, conductivity measurements, magnetic susceptibility data, electronic, IR and ESR spectroscopy. Cyclic voltammetric studies show that all complexes undergo quasi-reversible one-electron electrochemical reduction (CuII/CuI) in the potential range
0.17 – 0.36 V against Ag/AgCl reference electrode. On addition of CT-DNA to the Cu(II) complexes, there is increase in molar absorptivity as well as significant shift in lmax, indicating that the complex is strongly bound to CT-DNA.

 

 

 

Text Box: M= Co, Ni, Cu, Fe, Cr

 

Text Box: M/Al2O3

 

909

 

Catalytic allylic oxidation of cyclohexene with air over metal-containing Al2O3 catalysts

 

 

 

 

 

 

 

 

 

 

Q Zhang, Q-H Xia *, X-H Lu, H-J Zhan & G Xu

 

 

 

 

 

Transition metal-containing Al2O3 samples have been prepared by wet impregnation of powdered pseudo-boehmite (Al2O3) support with aqueous metal-containing salt solutions. Co/Al2O3 displays the best activity for the selective allylic oxidation of cyclohexene to 2-cyclohexen-1-one and 2-cyclohexen-1-ol, with about
34.3 mol% conversion of cyclohexene, 73.0% selectivity for
2-cyclohexen-1-one and 23.9% selectivity for 2-cyclohexen-1-ol.

 

Text Box: NEEN

 

916

 

Kinetics and mechanism of the nucleophilic ring opening of oxazolinone in mixed aqueous solvents

 

 

 

 

 

 

Amel M Ismail

 

 

 

Solvent effect on the kinetics of ring opening of oxazolinone has been investigated in neutral and alkaline medium in dioxan-water mixtures up to 50% v/v in the temperature range of 40-60°C. The isokinetic temperatures in both media (310, 303 and 298 K for neutral and alkaline hydrolysis by NaOH and Na2CO3 respectively) indicate that the reaction is entropy controlled and that solute-solvent interactions play an important role.

 

Notes

 

923

 

Theoretical investigation on the conformation of ethylene-norbornene copolymer chains

 

 

 

 

 

 

 

 

 

 

 

 

Sevil Savaşkan Yilmaz

 

 

 

Conformational analysis of ethylene-norbornene chains (E-N) has been carried out by AM1, MM2, AMBER and OPLS methods, taking into consideration the binding of ethylene monomers to norbornene monomers at various positions. The chain formed by connecting exo-endo positions of the monomers has lower torsional barrier energy and more flexibility than those formed with bonds at other positions. The analysis shows that the NEEN copolymer has the lowest strain energy.

 

 

 

929

 

Vibrational spectral and DFT studies of 7-azaindole adsorbed on silver nanometal surface

 

 

 

 

 

 

 

 

 

 

 

B Karthikeyan

 

 

 

Surface enhanced Raman scattering studies of 7-azaindole adsorbed on silver nanometal surface are reported. The bands show that 7-azaindole is adsorbed in tilted orientation. The observed enhancement factor is of the order of 104.

 

 

933

 

Influence of apolar aprotic solvents on proton transfer equilibrium between m-/o-chlorobenzoic acids and the carbinol base of crystal violet:
A chemometric analysis

 

 

 

 

 

 

Ruchi Shrivastava, Sangeeta Mishra &
Susanta K Sengupta*

 

 

 

Chemometric analysis of equilibrium results for apolar aprotic solvent effects on proton transfer between m-/o-chlorobenzoic acids and crystal violet carbinol base using Koppel-Palm’s approach shows that the total solvent effect is contributed mainly by dispersion and dipolar/electrostatic interactions in approximately 7:4 ratio.

 

937

 

Multinuclear NMR investigation on newly synthesized gold(I) pentafluorophenyl-arylazoimidazole complexes

 

 

 

 

 

 

 

 

 

 

Prithwiraj Byabartta* & Mariano Laguna

 

 

 

Reaction of [Au(C6F5)(tht)] with RaaiR/ in dichloromethane yields [Au(C6F5)(RaaiR/)] [RaaiR/ = p-R-C6H4-N=N-C3H2-NN-1-R/].

 

 

942

 

Synthesis, infrared and X-ray diffraction studies of mixed halogen sodalites and sodalites containing silver derivatives

 

 

 

 

 

 

A V Borhade, S G Wakchaure* & A G Dholi

 

 

 

Mixed halogen sodalites of the type Na8[AlSiO4]6Cl2-xBrx
and Na8[AlSiO4]6Br2-xIx (0£ x £2) have been prepared by
low temperature hydrothermal technique. Silver
containing derivatives, Na8-xAgx[AlSiO4]6(MnO4)2 and
Na8-xAgx[AlSiO4]6(ClO4)2, have also been obtained through aqueous ion exchange process.

 

 

947

 

Low-temperature heat capacity and standard
molar enthalpy of formation of crystalline
(S)(+)Ibuprofen (C13H18O2)(s)

 

 

 

 

 

 

 

 

 

You-Ying Di*, Chun-Tian Ye, Zhi-Cheng Tan & Guo-Ding Zhang

 

 

 

Low-temperature heat capacities of (S)–(+)–Ibuprofen have been measured by a precision automated adiabatic calorimeter in the temperature range 78 – 348 K. The smoothed heat capacities and thermodynamic functions have been calculated by the heat capacity polynomial equation. The constant-volume energy of combustion, DUc (C13H18O2, s), at 298.15 ± 0.001 K, is found to be – (7136.94 ± 4.74) kJ mol-1. The standard molar enthalpy of combustion of the sample, DcH(C13H18O2, s), is calculated to be – (7145.62 ± 4.74) kJ mol-1, while standard molar enthalpy of formation of the compound, DfH(C13H18O2, s), is derived to be – (542.48 ± 5.05) kJ mol-1.

952

 

Kinetics of reduction of [Co(NH3)5N3]Cl2 by iron (II)  in CTAB/n-heptane/butanol/water reverse micelles

 

 

 

 

 

 

 

 

 

 

 

 

Tapas Majumdar & Ambikesh Mahapatra*

 

 

 

Kinetics of reduction of pentaammineazidocobalt(III) chloride complex by ammonium ferrous sulphate has been studied in the water pools of cationic reverse micelles of cetyltrimethyl-ammonium bromide. The reaction is first order each in Co(III) complex and iron(II) in all water-to-surfactant molar ratios. A mechanism involving bimolecular azido-bridged inner-sphere intermediate complex formation between Co(III) complex and iron(II) is proposed.

 

 

 

 

 

 

 

 

 

 

957

 

Simultaneous determination of ascorbic acid, dopamine and uric acid using PEDOT polymer modified electrodes

 

 

 

 

S Radha Jeyalakshmi, S Senthil Kumar, J Mathiyarasu*, K L N Phani & V Yegnaraman

 

 

 

Dopamine, uric acid and ascorbic acid have been determined simultaneously on a poly (3,4-ethylenedioxythiophene) modified electrode. On bare glassy carbon electrode, all three undergo oxidation and appear as a single peak at ~ 200 mV, while on the modified electrode, distinct peaks with clear potential separation are observed. Detection limits of 7.4 mM, 1.2 mM and 1.4 mM for ascorbic acid, dopamine and uric acid, respectively are observed.

 

 

962

 

Micellar effects on the electrochemical oxidation of norepinephrine and its determination in the presence of ascorbic acid

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Yan Li, Xiao-Lin Wen & Zhong-Li Liu*

 

 

 

Significant micellar effects are observed in the electrooxidation of norepinephrine at glassy carbon electrode. The electrocatalytic oxidation of norepinephrine in the presence of ascorbic acid in SDS micelles enables a sensitive determination of norepinephrine in the presence of ascorbic acid. The oxidation peak current increases almost linearly with increasing concentration of norepinephrine in the range of 5 ´ 10-5 – 1.2 ´ 10-3 M and of ascorbic acid in the concentration range of 1 ´ 10-4 – 3 ´ 10-3 M. Ascorbic acid at concentrations up to 10 mM shows
no appreciable interference in the determination of
5
´ 10-5 – 1.2 ´ 10-3 M norepinephrine.

 

 

 

966

 

Book Review

 

 

 

 

Authors for correspondence are indicated by (*)


Indian Journal of Chemistry

Vol. 46A, June 2007, pp. 895-898

 

DFT studies on anionic hetero atom (N or/and S) substitution in TiO2

M Sathish, M Sankaran, B Viswanathan* & R P Viswanath

Received 17 January 2007; revised 24 April 2007

The variation in the band structure, band gap and stability of the hetero atom substituted TiO2 have been studied. Study shows that S doping has considerable role in the reduction of the band gap, Eg. In addition, it has been shown that sulphur doping at the oxide ion position is preferred.

 

Indian Journal of Chemistry

Vol. 46A, June 2007, pp. 899-903

 

Stereochemical configuration of poly (2-hydroxy ethyl methacrylate)by NMR spectroscopy

Sunita Hooda, * & Ashok Kumar Goyal

Received 1 September 2006; rerevised 13 April 2007

Poly (2-hydroxy ethyl methacrylate) has been prepared by free radical bulk polymerization at 80°C and characterization of its microstructure has been carried out using one-dimensional (1H, 13C{1H}) and two-dimensional (HSQC, TOCSY and HMBC) NMR spectra. The methyl, methylene and carbonyl carbon resonance signals have been found to be sensitive to various configurational sequences. 2D TOCSY spectrum has been used to examine the coupling between bonded protons. 2D HMBC spectrum shows long range coupling between quaternary, methylene and carbonyl carbon with methyl protons.

IPC Code: C08G61/00; G01N24/00

 

Indian Journal of Chemistry

Vol. 46A, June 2007, pp. 904-908

 

DNA interactions of mixed ligand copper(II) complexes with sulphur containing ligands

P Murali Krishna, K Hussain Reddy*, Pitchika G Krishna & G H Philip

Received 24 June 2006; revised 24 April 2007

Mixed ligand copper (II) complexes having the composition [Cu(tsc)Cl2](I), [Cu(tsc)2Cl2](II), [Cu(phen)Cl2](III), [Cu(dmso)2Cl2](IV), [Cu(phen)(tsc)Cl2](V) and [Cu(dmso)2(tsc)Cl2](VI) (where tsc = thiosemicarbazide, phen = ortho phenanthroline and dmso = dimethyl sulphoxide) have been synthesized and characterized on the basis of elemental analyses, conductivity measurements, magnetic susceptibility data, electronic, IR and ESR spectroscopy. Electrochemical behaviour of these complexes has been investigated by cyclic voltammetry. All complexes undergo quasi-reversible one-electron electrochemical reduction (CuII/CuI) in the potential range 0.17-0.36 V against Ag/AgCl reference electrode. The E1/2 values of mixed ligand complexes are less than the parent complexes, presumably due to the increase in ligand number and size of the complex. The binding studies of copper complexes with CT-DNA have been investigated using absorption spectrophotometry.

IPC Code: Int. Cl.8 C07F1/08

 

Indian Journal of Chemistry

Vol. 46A, June 2007, pp. 909-915

 

Catalytic allylic oxidation of cyclohexene with air over metal-containing Al2O3 catalysts

Q Zhang, Q-H Xia, *, X-H Lu, H-J Zhan & G Xu

 

Received 6 December 2006; revised 26 April 2007

Catalytic allylic oxidation of cyclohexene with air to 2-cyclohexen-1-one and 2-cyclohexen-1-ol over Co/Al2O3 catalysts under mild conditions has been reported. A series of transition metal-containing Al2O3 samples such as Co/Al2O3, Ni/Al2O3, Cu/Al2O3, Fe/Al2O3 and Cr/Al2O3, have been prepared by wet impregnation of powdered pseudo-boehmite (Al2O3) support with aqueous metal-containing salt solutions, followed by drying at 413 K overnight and calcination at 823 K for 6 h. Only Co/Al2O3 shows good activity for the selective oxidation of cyclohexene by air to 2-cyclohexen-1-one and 2-cyclohexen-1-ol in DMF. Under identical conditions, 34.3 mol% of cyclohexene is catalytically converted by Co/Al2O3 to achieve 73.0% selectivity to 2-cyclohexen-1-one and 23.9% selectivity to 2-cyclohexen-1-ol, which is superior to other catalysts.

IPC Code: Int. Cl.8 B01J21/04; B01J23/26; B01J23/72; B01J23/745; B01J23/75; B01J23/755; B01J33/00; B01J37/02

 

Indian Journal of Chemistry

Vol. 46A, June 2007, pp. 916-922

 

Kinetics and mechanism of the nucleophilic ring opening of oxazolinonein mixed aqueous solvents

Amel M Ismail

Received 1 September 2006; revised 25 March 2007

Solvent effect on the kinetics of ring opening of oxazolinone has been investigated in neutral and alkaline medium in dioxan-water mixtures up to 50% v/v in the temperature range of 40-60°C. The thermodynamic activation parameters have been calculated and discussed in terms of solvation effect. The isokinetic temperature in both media (310, 303 and 298 K for neutral, alkaline hydrolysis by NaOH and Na2CO3 respectively) indicates that the reaction is entropy controlled and that solute-solvent interactions play an important role. The correlation of logk2 against either Grunwald-Wientien Y values or log[H2O] was found to be linear, while the correlation between logk2 and the reciprocal of the dielectric constant was non-linear. The estimated value of the slope m in Grunwald relationship gives a value less than unity indicating SAN/SN2 mechanism. Mechanism for the oxazolinone ring opening has been proposed.

 

Indian Journal of Chemistry

Vol. 46A, June 2007, pp. 923-928

 

Theoretical investigation on the conformation of ethylene-norbornene copolymer chains

Sevil Savaşkan Yilmaz

Received 12 December 2006; revised 27 April 2007

The conformational analysis of ethylene-norbornene chains (E-N) has been carried out using AM1, MM2, AMBER and OPLS methods taking into consideration the possibility of binding the ethylene monomers to norbornene monomers at various positions, i.e. exo-exo, exo-endo, endo-endo. The chain that is formed by connecting exo-endo positions of the monomers has lower torsional barrier energy than those formed with bonds at other positions and has more flexibility. It has been determined that the lowest strain energy has also NEEN and NNEE tetrads. NEEN copolymer has the lowest strain energy according to the molecular mechanics methods. Using the molecular mechanics and semiempirical AM1 methods, 1-2-3-4 internal rotation angle (dihedral) (φ) for all E-N copolymers have been calculated.

 

Indian Journal of Chemistry

Vol. 46A, June 2007, pp. 929-932

 

Vibrational spectral and DFT studies of 7-azaindole adsorbed on silver nanometal surface

B Karthikeyan*

Received 12 December 2006; revised 11 April 2007

Surface Enhanced Raman Scattering (SERS) studies of 7-azaindole (7-AI) adsorbed on silver nanometal surface are reported here. The observed SERS spectra have been compared with the normal Raman spectral assignments. From the assignment of the observed SERS bands, possible orientation of the 7-AI adsorbed on the metal surface is presumed. DFT studies have been undertaken and normal mode displacements analysed for 7-AI for better assignment of normal Raman and SERS bands.

IPC Code: Int. Cl.8 B82B; G01N21/65

 

Indian Journal of Chemistry

Vol. 46A, June 2007, pp. 933-936

 

Influence of apolar aprotic solvents on proton transfer equilibrium betweenm-/o-chlorobenzoic acids and the carbinol base of crystal violet: A chemometric analysis

Ruchi Shrivastava, Sangeeta Mishra &Susanta K Sengupta*

Received 25 December 2006; revised 18 April 2007

A chemometric analysis of equilibrium results for apolar aprotic solvent effects on proton transfer betweenm-/o-chlorobenzoic acids and crystal violet carbinol base using Koppel-Palm’s approach shows that the total solvent effect is contributed mainly by dispersion and dipolar/electrostatic interactions in approximately 7:4 ratio. A parallel study with m- and o-fluorobenzoic acids but under conditions favouring acid-acid anion homoconjugation reflects the role of homoconjugated complexed acids in substantially modifying the detailed pattern of solvent effects.

 

Indian Journal of Chemistry

Vol. 46A, June 2007, pp. 937-941

 

Multinuclear NMR investigation on newly synthesized gold(I) pentafluorophenyl-arylazoimidazole complexes

Prithwiraj Byabartta* & Mariano Laguna

Received 25 July 2006; 23 April 2007

Reaction of [Au(C6F5)(tht)] with RaaiR¢ in dichloromethane yields [Au(C6F5)(RaaiR¢)] [RaaiR¢ = p-R-C6H4-N=N-C3H2-NN-1-R¢, (1-3), abbreviated as N,N¢-chelator, where N(imidazole) and N(azo) represent N and N¢, respectively, R = H, Me, Cl and R¢ = Me, CH2CH3, CH2Ph]. The maximum molecular peak of [Au(C6F5)(MeaaiMe)]­ is observed at m/z 564.01 in the FAB mass spectrum. IR spectra of the complexes show -C=N- and -N=N- stretching at 1590 and 1370 cm-1 and at 1510, 955, 800 cm-1 due to the presence of pentafluorophenyl ring. The 1H NMR spectral measurements suggest that methylene group in RaaiEt gives a complex AB multiplet with coupling constant of 7.6 Hz, while in RaaiCH2Ph, it shows AB type quartets with coupling constant of 7.2 Hz. 13C NMR spectrum of the complexes assign the molecular skeleton. In the 1H-1H COSY spectrum of the present complexes, absence of any off-diagonal peaks extending from d = 14.12 ppm and 9.55 ppm confirm no proton on N(1) and N(3) respectively. In the 1H-13C HMQC spectrum, since there are no contours atd = 157.12, 160.76, 155.67 ppm and 157.68—160.2 ppm, these may be assigned to the C(2), C(6), C(12) and C(13, 14, 15, 16 and 17) carbon atoms respectively. The solution structure and stereoretentive transformation in each step have been established from 1H NMR data. The electrochemistry gives the ligand reduction peaks.

IPC Code: Int. Cl.8 C07F1/12; G01N24/00

 

Indian Journal of Chemistry

Vol. 46A, June. 2007, pp. 942-946

 

Synthesis, infrared and X-ray diffraction studies of mixed halogen sodalites and sodalites containing silver derivatives

A V Borhade, S G Wakchaure, *, A G Dholi

Received 19 May 2006; revised 24 February 2007

Low temperature hydrothermal technique has been employed for the synthesis of different mixed halogen sodalites of the type Na8[AlSiO4]6Cl2-xBrx and Na8 [AlSiO4]6Br2-xIx (0£ x <2). The competition between chloride, bromide and iodide is also studied for the formation of mixed sodalites. Infrared spectroscopy has been used successfully for the confirmation of the framework structure and dopant. Significant IR frequency changes are observed in the region of 300-1200 cm-1 for symmetric, asymmetric and bending modes of vibration. This IR shift is found to be dependent on sample preparation. X-ray powder diffraction is used to establish the structure of mixed halogen sodalites. Further, silver containing derivatives, Na8-xAgx[AlSiO4]6(MnO4)2 and Na8-xAgx[AlSiO4]6(ClO4)2, are also obtained through aqueous ion exchange process. A relationship has been established between the amount of silver exchanged with IR frequency of asymmetric mode of vibration.

IPC Code: Int, Cl.8 B01J29/02; C01B33/26; G01N21/00

 

Indian Journal of Chemistry

Vol. 46A, June 2007, pp. 947-951

 

Low-temperature heat capacity and standard molar enthalpy of formation of crystalline (S)(+)Ibuprofen (C13H18O2)(s)

You-Ying Di,*, Chun-Tian Ye, Zhi-Cheng Tan & Guo-Ding Zhang

Received 8 November 2006; revised 30 April 2007

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 - H298.15K) and (ST - S298.15K), 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 DUc (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 cHm° (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, fHm° (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.

 

Indian Journal of Chemistry

Vol. 46A, June 2007, pp. 952-956

 

Kinetics of reduction of [Co(NH3)5N3]Cl2 by iron (II)  in CTAB/n-heptane/butanol/water reverse micelles

Tapas Majumdar & Ambikesh Mahapatra*

Received 8 September 2006; revised 25 April 2007

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, ∆H and standard entropy of activation, ∆S) of the reaction at different W values have been calculated which corroborate the kinetics of the reaction.

IPC Code: Int. Cl.8 C07B31/00

 

Indian Journal of Chemistry

Vol. 46A, June 2007, pp. 957-961

 

Simultaneous determination of ascorbic acid, dopamine and uric acid using PEDOT polymer modified electrodes

S Radha Jeyalakshmi, S Senthil Kumar, J Mathiyarasu*, K L N Phani & V Yegnaraman

Received 17 August 2006; revised 1 May 2007

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 carbon electrode, all three undergo oxidation and appear as a single peak at around 200 mV, whereas on the modified electrode, distinct peaks with clear potential separation are observed, paving way for their simultaneous determination. Detection limits of 7.4 mM, 1.2 mM and 1.4 mM for ascorbic acid, dopamine and uric acid, respectively are observed by pulse voltammetry. The possible interference from creatinine, norepinephrine, epinephrine, glucose, 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.

IPC Code: G01N27/30; G01N33/50

 

Indian Journal of Chemistry

Vol. 46A, June 2007, pp. 962-965

 

Micellar effects on the electrochemical oxidation of norepinephrine and its determination in the presence of ascorbic acid

Yan Li,  Xiao-Lin Wen & Zhong-Li Liu*

Received 6 September 2006; revised and accepted 21 March 2007

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.

IPC Code: Int. Cl.8 C07B33/00; C25B3/02; G01N27/00