South Africa

University of Durban-Westville

S.B. JONNALAGADDA (Ph. D.)

Department of Chemistry, University of Durban-Westville, Durban 4000, South Africa.

E-mail: jonna@pixie.udw.ac.za

Selected Publications

  1. Heavy metal uptake by two edible Amaranthus herbs grown on soils contaminated with lead, mercury, cadmium, and nickel,  Chunilall V, Kindness A, Jonnalagadda SB, Journal of Environmental Science and Health Part B-Pesticides Food Contaminants and Agricultural Wastes 40 (2): 375-384, 2005
  2. Uncatalysed and catalysed reaction of acidic chlorite with acridine orange, Pare B, Vijay R, Jonnalagadda SB, et al. Indian Journal of Chemistry Section A-Inorganic Bio-Inorganic Physical Theoretical & Analytical Chemistry 44 (2): 241-244, 2005
  3. Baijnath Y, Vasam C, Jonnalagadda SBA photometric method for ozone determination using alizarin violet. Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering 39 (9): 2485-2492, 2004
  4. Effluent treatment using electrochemically bleached seawater - oxidative degradation of pollutants,  Jonnalagadda SB, Nadupalli S. Talanta 64 (1): 18-22, 2004
  5. 5 Heavy metal uptake by Spinach leaves grown on contaminated soils with lead, mercury, cadmium, and nickel, Chunilall V, Kindness A, Jonnalagadda SB, Journal of Environmental Science and Health Part B-Pesticides Food Contaminants And Agricultural Wastes 39 (3): 473-481, 2004
  6. A user-friendly programme 'SIMKINE' for simulation of kinetics involving complex reaction mechanisms,  Jonnalagadda SB, Parumasur N, Shezi MN. Computational Biology and Chemistry 27 (2): 147-152, 2003
  7. Bhagwat VW, Pipada M, Jonnalagadda SB, et al. Kinetics and mechanism of C(16)TAB catalyzed oxidation of methylene violet by chlotamine-T in acidic medium. Indian Journal of Chemistry Section A-Inorganic Bio-Inorganic Physical Theoretical & Analytical Chemistry 42 (7): 1644-1648, 2003
  8. Uncatalyzed and ruthenium(III)-catalyzed reaction of acidic chlorite with methylene violet  Jonnalagadda SB, Shezi M, Pare B., INTERNATIONAL Journal of Chemical Kinetics 35 (7): 294-303, 2003
  9. Oxidative degradation of indigocarmine by hypochlorite - A tool for determination of hypochlorite in commercial samples, Harriram A, Govender V, Jonnalagadda SBJournal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering 38 (6): 1055-1064, 2003
  10. Seawater in treatment of waste waters, Chunilall V, Govender M, Jonnalagadda SB, Journal of Environmental Science and Health Part A-Toxic/Hazardous Substances & Environmental Engineering 37 (8): 1523-1531, 2002

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Technikon Pretoria

MCCRINDLE R.I. (Ph. D.)

Technikon Pretoria, Department of Chemistry and Physics, Private Bag X680, Pretoria 0001, South Africa.

Selected Publications

  1. A comparison of the performance of various synthetic gypsums in plant trials during the manufacturing of OPC clinker  Potgieter JH, Potgieter SS, McCrindle RI, Cement and Concrete Research 34 (12): 2245-2250, 2004
  2. Reductive separation and slurry nebulization of converter matte for ICP-OES analysis of some platinum group metals and gold  Mokgalaka NS, Wondimu T, McCrindle RI Journal of Analytical Atomic Spectrometry 19 (11): 1493-1497, 2004
  3. Mokgalaka NS, McCrindle RI, Botha BM. Multielement analysis of tea leaves by inductively coupled plasma optical emission spectrometry using slurry nebulisation  Journal of Analytical Atomic Spectrometry 19 (10): 1375-1378, 2004
  4. Mangena SJ, de Korte GJ, McCrindle RI, et al. The amenability of some Witbank bituminous ultra fine coals to binderless briquetting. Fuel Processing Technology 85 (15): 1647-1662, 2004
  5. Marjanovic L, McCrindle RI, Botha BM, et al. Use of a simplified generalized standard additions method for the analysis of cement, gypsum and basic slag by slurry nebulization ICP-OES. Analytical and Bioanalytical Chemistry 379 (1): 104-107, 2004
  6. Panichev N, McCrindle RIThe application of bio-indicators for the assessment of air pollution. Journal of Environmental Monitoring 6 (2): 121-123, 2004
  7. Archer M, McCrindle RI, Rohwer ER. Analysis of cobalt, tantalum, titanium, vanadium and chromium in tungsten carbide by inductively coupled plasma-optical emission spectrometry. Journal of Analytical Atomic Spectrometry 18 (12): 1493-1496, 2003
  8. Potgieter JH, Potgieter SS, McCrindle RI, et al. An investigation into the effect of various chemical and physical treatments of a South African phosphogypsum to render it suitable as a set retarder for cement. Cement and Concrete Research 33 (8): 1223-1227, 2003
  9. Potgieter JH, Potgieter SS, McCrindle RI, et al. Fingerprinting of South African cement clinkers and gypsum as a tool for cement identification purposes. Advances in Cement Research 15 (2): 45-50, 2003
  10. McCrindle RI, Marjanovic L. Slurry nebulization for the analysis of gypsum and cement by inductively coupled plasma spectrometry. Spectroscopy and Spectral Analysis 22 (6): 996-1004, 2002

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PANICHEV N. (Ph. D.)

Technikon Pretoria, Department of Chemistry and Physics, Private Bag X680, Pretoria 0001, South Africa.

Selected Publications

  1. Electrothermal atomic absorption spectrometric determination of vanadium(V) in soil after leaching with Na 2CO 3, Mandiwana KL, Panichev N. Analytica Chimica Acta 517 (1-2): 201-206, 2004
  2. Determination of hexavalent chromium in South African cements and cement-related materials with electrothermal atomic absorption spectrometry, Potgieter SS, Panichev N, Potgieter JH, et al. Cement And Concrete Research 33 (10): 1589-1593, 2003
  3. Panichev N, McCrindle RI. The application of bio-indicators for the assessment of air pollution. Journal of Environmental Monitoring 6 (2): 121-123, 2004.
  4. Panichev N, Mandiwana K, Foukaridis G. Electrothermal atomic absorption spectrometric determination of Cr(VI) in soil after leaching of Cr(VI) species with carbon dioxide. Analytica Chimica Acta 491 (1): 81-89, 2003
  5. Determination of cadmium in tobacco smoke by electrothermal atomic absorption spectroscopy with electrostatic precipitation of samples on the graphite tube atomizer, Altman EL, Panichev NA, Journal De Physique IV 107: 37-40 Part 1. 2003.
  6. Determination of lead and cadmium in organic solutions by electrothermal atomic absorption spectrometry with a transverse heated filter atomizer, Mbileni CN, Ngobeni P, Katskov DA, et al., Journal of Analytical Atomic Spectrometry 17 (3): 236-241, 2002.
  7. Mbileni CN, Ngobeni P, Katskov DA, et al. Determination of lead and cadmium in organic solutions by electrothermal atomic absorption spectrometry with a transverse heated filter atomizer (vol 17, pg 236, 2002). Journal of Analytical Atomic Spectrometry 17 (3): 319-319, 2002.
  8. Performance of the transverse heated filter atomizer for the atomic absorption determination of mercury, Marais PJJG, Panichev NA, Katskov DA. Journal of Analytical Atomic Spectrometry 15 (12): 1595-1598, 2000.
  9. Condensation of analyte vapor species in graphite furnace atomic absorption spectrometry,  Panichev NA, Ma Q, Sturgeon RE, et al. Spectrochimica Acta Part B-Atomic Spectroscopy 54 (5): 719-731, 1999
  10. Panichev N , Sturgeon RE. Atomic absorption by free atoms in solution following chemical reduction from the ionic stat. Analytical Chemistry 70 (9): 1670-1676, 1998.

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PANICHEVA S. (Ph. D.)

Technikon Pretoria, Department of Chemistry and Physics, Private Bag X680, Pretoria 0001, South Africa.

Selected Publications

  1. Investigation into methods of chloride analysis of South African cement and cement-related materials with low chloride concentrations  Potgieter SS, Potgieter JH, Panicheva S. Materials and Structures 37 (267): 155-160, 2004.
  2. Determination of hexavalent chromium in South African cements and cement-related materials with electrothermal atomic absorption spectrometry, Potgieter SS, Panichev N, Potgieter JH, Panicheva S. Cement And Concrete Research 33 (10): 1589-1593, 2003.
  3. Properties of a Mercury-Plated Graphite Electrode in Chloride Solution  Panicheva SE, Filanovskii Bk. Journal of Analytical Chemistry of the USSR 44 (11): 1638-1641 Part 2, 1989.
  4. Comparison of Glassy-Carbon and Carbosital Electrodes in Electrochemical Stripping Analysis  Panicheva SE, Filanovskii BK. Industrial Laboratory 55 (5): 519-521, 1989.

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POTGIETER J.H. (Ph. D.)

Technikon Pretoria, Department of Chemical and Metallurgical Engineering, Private Bag X680, Pretoria 0001, South Africa.

Selected Publications

  1. Potgieter JH, Potgieter SS, Mbaya RKK, et al. Small-scale recovery of noble metals from jewellery wastes. Journal of the South African Institute of Mining and Metallurgy 104 (10): 563-571, 2004.
  2. Potgieter JH, Godoi RHM, van Grieken R. A case study of high-temperature corrosion in rotary cement kilns. Journal of the South African Institute of Mining and Metallurgy 104 (10): 603-606, 2004.
  3. Potgieter JH, Potgieter SS, McCrindle RI. A comparison of the performance of various synthetic gypsums in plant trials during the manufacturing of OPC clinker. Cement and Concrete Research 34 (12): 2245-2250, 2004.
  4. Potgieter SS, Potgieter JH, Panicheva S. Investigation into methods of chloride analysis of South African cement and cement-related materials with low chloride concentrations. Materials and Structures 37 (267): 155-160, 2004.
  5. Potgieter SS, Panichev N, Potgieter JH, et al. Determination of hexavalent chromium in South African cements and cement-related materials with electrothermal atomic absorption spectrometry. Cement and Concrete Research 33 (10): 1589-1593, 2003.
  6. Potgieter JH , Potgieter SS, Strydom CA, et al..The influence of various common ions on the slaking of some South African limes. Water SA 29 (4): 433-436, 2003.
  7. Potgieter JH , Potgieter SS, McCrindle RI, et al. An investigation into the effect of various chemical and physical treatments of a South African phosphogypsum to render it suitable as a set retarder for cement. Cement and Concrete Research 33 (8): 1223-1227, 2003.
  8. Potgieter JH , Potgieter SS, de Waal D. An empirical study of factors influencing lime slaking Part II: Lime constituents and water composition. Water SA 29 (2): 157-160, 2003.
  9. Agyei NM, Strydom CA, Potgieter JH. Reply to the discussion by A. Demirbas of the paper "The removal of phosphate ions from aqueous solution by fly ash, slag, ordinary Portland cement and related blends". Cement And Concrete Research 33 (6): 937-937, 2003.
  10. Potgieter JH , Potgieter SS, McCrindle RI, et al. Fingerprinting of South African cement clinkers and gypsum as a tool for cement identification purposes Advances in Cement Research 15 (2): 45-50, 2003.

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University of Stellenbosch

KOCH K. R. (Ph. D.)

Department of Chemistry, University of Stellenbosch, P Bag X1, Matieland, 7602, South Africa

Research Interests

  • Design and synthesis of PGM-selective ligands and a study of their co-ordination of these metal ions in solution.
  • Design and synthesis of PGM-selective resins for precious metal recovery and pre-concentration from process effluents and spent catalysts.
  • Application of high resolution, multi-nuclear magnetic resonance spectroscopy in speciation, solution dynamics and structure elucidation of metals complexes.
  • Speciation of metal complexes in solution chromatographic and other methods of separation of metal complexes.
  • Atomic spectroscopic (ICP and ICPMS) determination of metals in simple and complex matrices.
  • Design and study of new biologically active (eg Anti-malarial and anti-neoplastic) complexes of platinum group metals.

Selected Publications

  1. Hallale O, Bourne SA, Koch KR. Metallamacrocyclic complexes of Ni(II) with 3,3,3 ',3 '-tetraalkyl-1,1 '-aroylbis(thioureas): crystal and molecular structures of a 2 : 2 metallamacrocycle and a pyridine adduct of the analogous 3 : 3 complex. Crystengcomm 7: 161-166, 2005
  2. Hanekom D, McKenzie JM, Derix NM, et al.. Photoinduced isomerisation of cis-[M(L-S,O)(2)] (M = Pt-II and Pd-II) complexes of N,N-diethyl-N'-3,4,5-trimethoxybenzoylthiourea: key to preparation of the trans isomer. Chemical Communications (6): 767-769, 2005
  3. Bourne SA, Hallale O, Koch KR. Hydrogen-bonding networks in a bipodal acyl-thiourea and its Ni-II 2 : 2 metallamacrocyclic complex. Crystal Growth & Design 5 (1): 307-312, 2005
  4. Blewett G, Esterhuysen C, Bredenkamp MW, et al. The first bipodal thiocarbamic acid ester, O,O '-diethyl N,N '-(p-phenylenedicarbonyl)bis(thiocarbamate). Acta Crystallographica Section C-Crystal Structure Communications 60: O862-O864 Part 12, 2004
  5. McKenzie JM, Koch KR. Rapid analysis of major components and potential authentication of South African olive oils by quantitative C-13 nuclear magnetic resonance spectroscopy. South African Journal of Science 100 (7-8): 349-354, 2004
  6. Keay SK, Szekely Z, Conrads TP, et al. An antiproliferative factor from interstitial cystitis patients is a frizzled 8 protein-related sialoglycopeptide. Proceedings of the National Academy of Sciences of the United States of America 101 (32): 11803-11808, 2004
  7. Westra AN, Esterhuysen C, Koch KR. Intramolecular hydrogen-bond-directed coordination: trans-bis-(N-benzoyl-N '-propylthiourea-kappa S)-diiodoplatinum(II) and trans-bis-(N-benzoyl-N '-propylthiourea-kappa S)-dibromoplatinum(II). Acta Crystallographica Section C-Crystal Structure Communications 60: M395-M398 Part 8, 2004
  8. Egan TJ, Koch KR, Swan PL, et al. In vitro antimalarial activity of a series of cationic 2,2 '-bipyridyl- and 1,10-phenanthrolineplatinum(II) benzoylthiourea complexes. Journal of Medicinal Chemistry 47 (11): 2926-2934, 2004
  9. Vanhaecke F, Resano M, Garcia-Ruiz E, et al. Laser ablation-inductively coupled plasma-dynamic reaction cell-mass spectrometry (LA-ICP-DRC-MS) for the determination of Pt, Pd and Rh in Pb buttons obtained by fire assay of platiniferous ores. Journal of Analytical Atomic Spectrometry 19 (5): 632-638, 2004
  10. Kramer J, Driessen WL, Koch KR, et al. Highly selective and efficient recovery of Pd, Pt, and Rh from precious metal-containing industrial effluents with silica-based (poly)amine ion exchangers. Separation Science and Technology 39 (1): 63-75, 2004

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PRIOR .B (Ph. D.)

University of Stellenbosch, P Bag X1, Matieland, 7602, South Africa

Selected Publications

  1. Mapolelo M, Torto N, Prior B. Evaluation of yeast strains as possible agents for trace enrichment of metal ions in aquatic environments. Talanta 65 (4): 930-937 FEB 28 2005

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University of Venda

MAKHAFOLA M. (Ph. D.)

University of Venda for S & T, Department of Chemistry, Private Bag X5050, Thohoyandou 0950, Limpopo Province, South Africa

Selected Publications

  1. Stefan RI, Makhafola MA, van Staden JF. Bienzymatic amperometric sensor for protein assay in milk. Preparative Biochemistry & Biotechnology 32 (2): 135-142, 2002
  2. van Staden JF, Makhafola M. Simultaneous spectrophotometric determination of nitrate and nitrite in foodstuffs and water by flow injection analysis. South African Journal of Chemistry-Suid-Afrikaanse Tydskrif Vir Chemie 52 (1): 49-54, 1999
  3. vanStaden JF, Makhafola MA, deWaal D. Kinetic study of the decomposition of nitrite to nitrate in acid samples using Raman spectroscopy. Applied Spectroscopy 50 (8): 991-994, 1996
  4. VanStaden JF, Makhafola MA. Spectrophotometric determination of nitrite in foodstuffs by flow injection analysis. Fresenius Journal of Analytical Chemistry 356 (1): 70-74, 1996.

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University of the Western Cape

MANUEL IWUOHA (Ph. D.)

University of the Western Cape, Dept of Chemistry, Belleville 7535, South Africa, e-mail:eiwuoha@uwc.ac.za

Research Interests

  • Electrochemistry, electroanalytical chemistry and biosensors

Selected Publications

  1. Morrin A, Moutloali RM, Killard AJ, et al. Organic phase cyclopentadienylnickelthiolate sensor system for electrochemical determination of sulfur dioxide. Electroanalysis 16 (23): 1944-1948, 2004
  2. Morrin A, Moutloali RM, Killard AJ, et al. Electrocatalytic sensor devices: (I) cyclopentadienylnickel(II) thiolato Schiff base monolayer self-assembled on gold. Talanta 64 (1): 30-38, 2004
  3. Somerset VS, Petrik LF, White RA, et al. The use of X-ray fluorescence (XRF) analysis in predicting the alkaline hydrothermal conversion of fly ash precipitates into zeolites. Talanta 64 (1): 109-114, 2004
  4. Mathebe NGR, Morrin A, Iwuoha EI. Electrochemistry and scanning electron microscopy of polyaniline/peroxidase-based biosensor. Talanta 64 (1): 115-120, 2004
  5. Iwuoha EI , Williams-Dottin AR, Hall LA, et al. Electrochemistry and application of a novel monosubstituted squarate electron-transfer mediator in a glucose oxidase-doped poly(phenol) sensor. Pure and Applied Chemistry 76 (4): 789-799, 2004
  6. Brahim S, Wilson AM, Narinesingh D, et al. Chemical and biological sensors based on electrochemical detection using conducting electroactive polymers. Microchimica Acta 143 (2-3): 123-137, 2003
  7. Iwuoha EI , Wilson A, Howel M, et al.. Cytochrome P450(2D6) (CYP2D6) bioelectrode for fluoxetine Analytical Letters 37 (5): 929-941, 2004
  8. Iwuoha EI , Smyth MR. Reactivities of organic phase biosensors: 6. Square-wave and differential pulse studies of genetically engineered cytochrome P450(cam) (CYP101) bioelectrodes in selected solvents. Biosensors & Bioelectronics 18 (2-3): 237-244, 2003
  9. Iwuoha EL , Williams AR, Hall LA. Novel electron transfer mediators for amperometric bioelectrodes: Introduction of methylsquarate and phenylsquarate. Electroanalysis 14 (17): 1177-1184, 2002
  10. Moutloali RM, Nevondo FA, Darkwa J, et al. Bimetallic nickel complexes with bridging dithiolato Schiff base ligands: synthesis, mass spectral characterisation and electrochemistry. Journal of Organometallic Chemistry 656 (1-2): 262-269.

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JAMES DARKWA (Ph. D.)

Department of Chemistry, University of the Western Cape

Private Bag X 17, Bellville 7535; South Africa

Research Interests

  • Coordination and organometallic chemistry of group 10 metals ans their applications as acetylene oligomerisation and polymerisation catalysts.

Selected Publications

  1. Guzei IA , Li KL, Darkwa J. Conformational studies of 1-4-bis(3,5-di-tert-butylpyrazolyl-1-carbonyl)benzene. Journal of Chemical Crystallography 35 (3): 197-202, 2005
  2. Osei-Twum EY, Litorja LA, Darkwa J, et al. Mass spectral Behavior of some homoleptic and mixed aryldichalcogenide bis(diphenylphosphino)ferrocenenickel(II), palladium(II), and platinum(II), and bis(diisopropylphosphino)ferrocenepalladium(II) complexes. Journal of the American Society for Mass Spectrometry 16 (1): 94-99, 2005
  3. Morrin A, Moutloali RM, Killard AJ, et al. Organic phase cyclopentadienylnickelthiolate sensor system for electrochemical determination of sulfur dioxide. Electroanalysis 16 (23): 1944-1948, 2004
  4. Morrin A, Moutloali RM, Killard AJ, et al. Electrocatalytic sensor devices: (I) cyclopentadienylnickel(II) thiolato Schiff base monolayer self-assembled on gold. Talanta 64 (1): 30-38, 2004
  5. Nelana SM, Darkwa J, Guzei IA, et al. Ethylene polymerization catalyzed by substituted pyrazole nickel complexes. Journal of Organometallic Chemistry 689 (10): 1835-1842, 2004
  6. Darkwa J , Olojo R, Chikwana E, et al. Antioxidant chemistry: Oxidation of L-cysteine and its metabolites by chlorite and chlorine dioxide. Journal of Physical Chemistry A 108 (26): 5576-5587, 2004
  7. Moloto MJ, Nelana SM, Moutloali RM, et al. Cyclopentadienylnickel thiolate complexes: synthesis, molecular structures and electrochemical detection of sulfur dioxide adducts. Journal of Organometallic Chemistry 689 (2): 387-394, 2004
  8. Darkwa J , Olojo R, Olagunju O, et al. Oxyhalogen-sulfur chemistry: Oxidation of N-acetylcysteine by chlorite and acidic bromate. Journal of Physical Chemistry A 107 (46): 9834-9845, 2003
  9. Li KL, Guzei IA, Darkwa J. Insertion of sulfur dioxide into metal-carbon bonds of chloro(methyl)palladium complexes. Polyhedron 22 (6): 805-810, 2003
  10. Guzei IA, Li KL, Bikzhanova GA, et al. Benzenedicarbonyl and benzenetricarbonyl linker pyrazolyl complexes of palladium(II): synthesis, X-ray structures and evaluation as ethylene polymerisation catalysts. Dalton Transactions (4): 715-722, 2003.

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Rhodes University

NYOKONG, T . (Ph. D.)

Department of Chemistry, Rhodes University, Grahamstown, 6140. South Africa.

* E-mail: t.nyokong@ru.ac.za. Fax +27-46-6322.

Selected Publications

  1. Ozoemena KI, Nyokong T. Surface electrochemistry of iron phthalocyanine axially ligated to 4-mercaptopyridine self-assembled monolayers at gold electrode: Applications to electrocatalytic oxidation and detection of thiocyanate. Journal Of Electroanalytical Chemistry 579 (2): 283-289, 2005
  2. Seotsanyana-Mokhosi I, Nyokong T. Synthesis and photochemical studies of substituted adjacent binaphthalophthalocyanines. Journal of Porphyrins and Phthalocyanines 8 (10): 1214-1221, 2004
  3. Nyokong T , Isago H. The renaissance in optical spectroscopy of phthalocyanines and other tetraazaporphyrins. Journal of Porphyrins and Phthalocyanines 8 (9): 1083-1090, 2004
  4. Zhao ZX, Ozoemena KI, Maree DM, et al. Synthesis and electrochemical studies of a covalently linked cobalt(II) phthalocyanine-cobalt(II) porphyrin conjugate. Dalton Transactions (7): 1241-1248, 2005
  5. Maharaj DS, Molell H, Antunes EM, et al. Melatonin generates singlet oxygen on laser irradiation but acts as a quencher when irradiated by lamp photolysis. Journal of Pineal Research 38 (3): 153-156, 2005
  6. Obirai J, Bedioui F, Nyokong T. Electro-oxidation of phenol and its derivatives on poly-Ni(OH)TPhPyPc modified vitreous carbon electrodes. Journal of Electroanalytical Chemistry 576 (2): 323-332, 2005
  7. Rodrigues NP, Obirai J, Nyokong T, et al. Electropolymerized pyrrole-substituted manganese phthalocyanine films for the electroassisted biomimetic catalytic reduction of molecular oxygen. Electroanalysis 17 (2): 186-190, 2005
  8. Agboola B, Ozoemena KI, Nyokong T. Hydrogen peroxide oxidation of 2-chlorophenol and 2,4,5-trichlorophenol catalyzed by monomeric and aggregated cobalt tetrasulfophthalocyanine. Journal of Molecular Catalysis A-Chemical 227 (1-2): 209-216, 2005
  9. Obirai J, Nyokong T. Electrochemical and catalytic properties of chromium tetraaminophthalocyanine. Journal of Electroanalytical Chemistry 573 (1): 77-85, 2004
  10. Ozoemena KI, Stefan RI, Nyokong T. Determination of 2',3-dideoxyinosine using iron (II) phthalocyanine modified carbon paste electrode. Analytical Letters 37 (13): 2641-2648, 2004

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University of Pretoria

STEFAN R. I. (Ph. D.)

Department of Chemistry, University of Pretoria, Pretoria 0002, South Africa .

Research Interests

My research centres mainly around bioanalysis with emphasis on electrochemical sensors:

  • new theoretical concepts concerning potential development for the potentiometric, membrane electrodes;
  • design;
  • characterization;
  • implementation in flow systems.

Chiral discrimination became increasingly important especially in the pharmaceutical industry. The utilization of electrochemical sensors (potentiometric, enantioselective membrane electrodes, amperometric biosensors, immunosensors) in chiral discrimination of the enantiomers is investigated by our group. Simultaneous detection of enantiomers and of different antigens using electrochemical sensors/sequential injection analysis systems is applied for the enantiopurity tests of pharmaceutical compounds.

The development of electrochemical sensors for the diagnosis of HIV, tuberculosis, malaria and hepatitis B will greatly facilitate the detection of patients before they become clinically ill. The treatment at an early stage will improve the chances of full recovery. Normally, the diagnostic facilities are only to be found in sophisticated laboratories in major centres. This technique will place the diagnostic modalities within the reach of a clinical nurse. Large segments (or even the whole) of the population could be screened at extremely low cost (a fraction of current expenditures) with minimal or no specific training of the operator.

Because the reliability of an analytical method is one of the parameters that must be considered for its validation, my research is also concentrated in the method uncertainties' sources, assurance of quality of the analytical information, interconnection between sample, method and instrument in analytical chemistry

Selected Publications

  1. "Quality and Reliability in Analytical Chemistry" G.E. Baiulescu, R.I. Stefan and H.Y. Aboul-Enein CRC Press, Boca Raton, Florida, USA, 2000.
  2. Ion - Selective Membrane Electrodes Based on Ion - Pair Complexes: Correlation Between Slopes and Stability of Ion - Pair Complexes R.I. Stefan and H.Y. Aboul-Enein, Instrum. Sci. &Technol., 27(2), 105-110, 1999.
  3. Lauryl Sulphate as Counter Ion for Construction of Ion - Selective Membrane Electrodes for Moclobemide and Disopyramide R.I. Stefan Anal. Chim. Acta, 350(1-2), 105-108, 1997.
  4. A New Construction for a Potentiometric, Enantioselective Membrane Electrode. Its Utilization to the S - Captopril Assay R.I. Stefan, J.F. van Staden and H.Y. Aboul-Enein Talanta, 48(5), 1139-1143, 1999.
  5. An Amperometric Biosensors / SIA System for the Simultaneous Determination of S and R Captopril R.I. Stefan, J.F. van Staden and H.Y. Aboul-Enein Biosens. Bioelectron., 15(1-2), 1-5, 2000.
  6. Determination of Urinary Oxalate Using Oxalate - Selective Membrane Electrodes R.I.Stefan, I. Draghici and G.E. Baiulescu Sens. Actuators B, 65(1-3), 250-252, 2000.
  7. Stefan, R-I., Van Staden, JF., Aboul-Enein, HY., Maltodextrins as new chiral selectors in the design of potentiometric, enantioselective membrane electrodes, Fresenius Journal of Analytical Chemistry (2001) 370, pp33-37
  8. Stefan, R-I., Aboul-Enein, HY., Van Staden, JF., Enantioselective Electrochemical Sensors, Sensors Update 10 (2002), pp124-139
  9. Ozoemena KI , Stefan RI. Enantioselective potentiometric membrane electrodes based on alpha, beta- and gamma-cyclodextrins as chiral selectors for the assay of L-proline. Talanta 66 (2): 501-504, 2005
  10. Ozoemena KI , Stefan RI, van Staden JF, et al. Enantioanalysis of S-perindopril using different cyclodextrin-based potentiometric sensors. Sensors and Actuators B-Chemical 105 (2): 425-429, 2005
  11. Ozoemena KI , Stefan RI, Nyokong T. Determination of 2',3-dideoxyinosine using iron (II) phthalocyanine modified carbon paste electrode. Analytical Letters 37 (13): 2641-2648, 2004
  12. Ozoemena KI , Stefan RI, van Staden JF, et al. Enantioselective, potentiometric membrane electrode, based on vancomycin as chiral selector, for the assay of S-perindopril. Instrumentation Science & Technology 32 (4): 371-378, 2004
  13. Ozoemena KI , Stefan RI, van Staden JF, et al. Utilization of maltodextrin based enantio selective, potentiometric membrane electrodes for the enantio selective assay of S-perindopril. Talanta 62 (4): 681-685, 2004
  14. Ozoemena KI , Stefan RI. Enantio selective, potentiometric membrane electrodes based on maltodextrins. Their applications for the determination of L-proline. Sensors and Actuators B-Chemical 98 (1): 97-100, 2004

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DANITA DeWAAL (Ph. D.)

Department Of Chemistry University of Pretoria, Pretoria 0002 South Africa. Tel.: +27124203539; Fax: +27123625297

Research Interests

Raman spectroscopic identification of the blue Ming porcelain pigment

The blue pigment, used for the decoration of Chinese blue and white porcelain-ware from the Ming-dynasty (1368 - 1644), was investigated using Raman spectroscopy. The Raman spectrum of the blue pigment was compared with various possible cobalt containing compounds. The shards on which the recordings were made, came from 16th and 17th century Portuguese shipwrecks around the South African coast, and were washed up on the beaches in the vicinity of the wrecks. These shards were obtained from the J A van Tilburg collection on campus. The Raman spectrum of the pigment was not available in existing Raman databases and the cobalt blue pigment had to be prepared by high temperature synthesis in this UP laboratory. As the commercial equivalent of the pigment that was obtained from Germany appeared to contain unwanted additives that interfered with the Raman spectrum, it could not be used for the purpose of identification. The Raman spectrum corresponded to that of the crystalline phase of the spinel CoAl 2O 4, which could be prepared from a mixture of cobalt and aluminium salts at a temperature of around 1000 degrees Celsius. The pigment could thus be characterized as cobalt aluminate, cobalt blue or Thenard's blue, which is probably the most popular modern day cobalt-containing pigment that was first synthesised in the western world during the 18th century.

Selected Publications

  1. FT-IR spectra of cadmium calcium pyrophosphate deWaal D, Hutter C Mikrochimica Acta 243-244 Suppl. 14, 1997. 
  2. Kinetic study of the decomposition of nitrite to nitrate in acid samples using Raman spectroscopy vanStaden JF, Makhafola MA, deWaal D Applied Spectroscopy 50 (8): 991-994 AUG 1996

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Van STADEN J. F. (Ph. D.)

Department of Chemistry, University of Pretoria,

Selected Publications

  1. Stefan RI, Nejem WM, van Staden JF, et al. Determination of D-2-hydroxyglutaric acid in urine samples using enantioselective, potentiometric membrane electrodes based on antibiotics. Sensors and Actuators B-Chemical 106 (2): 791-795, 2005
  2. Ozoemena KI, Stefan RI, van Staden JF, et al. Enantioanalysis of S-perindopril using different cyclodextrin-based potentiometric sensors. Sensors and Actuators B-Chemical 105 (2): 425-429, 2005
  3. Nejem RM, Stefan RI, van Staden JF, et al. Enantioanalysis of L-2-hydroxyglutaric acid in urine samples using enantioselective, potentiometric membrane electrodes based on maltodextrins. Talanta 65 (2): 437-440, 2005
  4. Stefan RI, van Staden JF, Bala C, et al. On-line assay of the S-enantiomers of enalapril, ramipril and pentopril using a sequential injection analysis/amperometric biosensor system. Journal of Pharmaceutical and Biomedical Analysis 36 (4): 889-892, 2004
  5. van Staden JF , Burguera JL. Editorial to ICFIA XII Conference SI. Talanta 64 (5): 1067-1070, 2004
  6. van Staden JF. An analytical chemist of stature and pioneer in flow analysis: Gary Dale Christian. Talanta 64 (5): 1071-1075, 2004
  7. van Staden JF , Stefan RI. Chemical speciation by sequential injection analysis: an overview. Talanta 64 (5): 1109-1113, 2004
  8. Tesfaldet ZO, van Staden JF, Stefan RI. Sequential injection spectrophotometric determination of iron as Fe(II) in multi-vitamin preparations using 1,10-phenanthroline as complexing agent. Talanta 64 (5): 1189-1195, 2004
  9. van Staden JF, Mulaudzi LV, Stefan RI. Spectrophotometric determination of bromate by sequential injection analysis. Talanta 64 (5): 1196-1202, 2004
  10. van Staden JF, Taljaard RE. Determination of lead(II), copper(II), zinc(II), cobalt(II), cadmium(II), iron(III), mercury(II) using sequential injection extractions. Talanta 64 (5): 1203-1212, 2004.

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University of Venda for Science and Technology

CHIMUKA L . (Ph. D.)

Department of Ecology and Resource Management, University of Venda for Science and Technology, P/Bag x5050, Thohoyandou, South Africa, 0950

E-mail: Chimuka@univen.ac.za

Research Interest

Pollution and waste management, in particular phytoremediation. Furthermore, I am developing novel techniques for extraction of pollutants from water bodies based on membranes and molecularly imprinted polymers.

Selected Publications

  1. Smith CB, Sims K, Chimuka L, et al. Kimberlite metasomatism at Murowa and Sese pipes, Zimbabwe. Lithos 76 (1-4): 219-232, 2004
  2. Cukrowska E, Chimuka L, Nsengimana H, et al.. Application of supported liquid membrane probe for extraction and preconcentration of organotin compounds from environmental water samples. Analytica Chimica Acta 523 (1): 141-147, 2004
  3. Chimuka L , Majors RE. Speciation studies of metal ions in environmental and biological media using supported liquid membrane extraction. LC GC Europe 17 (7): 396+, 2004
  4. Chimuka L , Cukrowska E, Jonsson JA. Why liquid membrane extraction is an attractive alternative in sample preparation. Pure and Applied Chemistry 76 (4): 707-722, 2004
  5. Chimuka L , Majors RE. Speciation studies of metal ions in environmental and biological media using supported liquid membrane extraction. LC GC North America 22 (2): 102+, 2004
  6. Chimuka L , Cukrowska E, Soko L, et al. Supported-liquid membrane extraction as a selective sample preparation technique for monitoring uranium in complex matrix samples. Journal of Separation Science 26 (6-7): 601-608, 2003
  7. Soko L, Chimuka L, Cukrowska E, et al. Extraction and preconcentration of manganese(II) from biological fluids (water, milk and blood serum) using supported liquid membrane and membrane probe methods. Analytica Chimica Acta 485 (1): 25-35, 2003
  8. Jung V, Chimuka L, Jonsson JA, et al. Supported liquid membrane extraction for identification of phenolic compounds in the nutrient solution of closed hydroponic growing systems for tomato. Analytica Chimica Acta 474 (1-2): 49-57, 2002
  9. Soko L, Cukrowska E, Chimuka L. Extraction and preconcentration of Cr(VI) from urine using supported liquid membrane. Analytica Chimica Acta 474 (1-2): 59-68, 2002
  10. Megersa N, Chimuka L, Solomon T, et al. Automated liquid membrane extraction and trace enrichment of triazine herbicides and their metabolites in environmental and biological samples. Journal Of Separation Science 24 (7): 567-576, 2001

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University of the Witwatersrand

CUKROWSKA E. (Ph. D.)

School of Chemistry, University of the Witwatersrand, Private Bag 3, PO Wits 2050, South Africa

E-mail: Ewa@chem.wits.ac.za

Research interests

Environmental Analytical Chemistry - Speciation of heavy metals in industrial, environmental, and biomedical samples.

Dr. Ewa Cukrowska is involved in the development and application of different analytical techniques for study of speciation of toxic heavy metals; she is looking at their transport, fate, seasonal changes, and biological uptake using chemometric evaluation and computer modelling.

Some of her research projects undertaken:

  • speciation of chromium(III)/(VI) in environmental waters and biological fluids;
  • speciation of manganese in biological fluids;
  • transport and fate of uranium in the environment of Gauteng;
  • study of water-sediment equilibria;
  • soil leaching experiments for the assessment of the mobility of metals; biological uptake of heavy metals by plants;
  • tadpoles as bioindicators of aquatic health;
  • development of separation and preconcentration methods for metals in biological matrices

Selected Publications

  1. Haywood LK, Alexander GJ, Byrne MJ, et al. Xenopus laevis embryos and tadpoles as models for testing for pollution by zinc, copper, lead and cadmium. African Zoology 39 (2): 163-174, 2004
  2. Cukrowska E, Chimuka L, Nsengimana H, et al. Application of supported liquid membrane probe for extraction and preconcentration of organotin compounds from environmental water samples. Analytica Chimica Acta 523 (1): 141-147, 2004
  3. Chimuka L, Cukrowska E, Jonsson JA. Why liquid membrane extraction is an attractive alternative in sample preparation. Pure And Applied Chemistry 76 (4): 707-722, 2004
  4. Cukrowska EM , Govender K, Viljoen M. Ion mobility based on column leaching of South African gold tailings dam with chemometric evaluation. Chemosphere 56 (1): 39-50, 2004
  5. Chimuka L, Cukrowska E, Soko L, et al. Supported-liquid membrane extraction as a selective sample preparation technique for monitoring uranium in complex matrix samples. Journal Of Separation Science 26 (6-7): 601-608, 2003
  6. Soko L, Chimuka L, Cukrowska E, et al. Extraction and preconcentration of manganese(II) from biological fluids (water, milk and blood serum) using supported liquid membrane and membrane probe methods. Analytica Chimica Acta 485 (1): 25-35, 2003
  7. Naicker K, Cukrowska E, McCarthy TS. Acid mine drainage arising from gold mining activity in Johannesburg, South Africa and environs. Environmental Pollution 122 (1): 29-40 2003
  8. Soko L, Cukrowska E, Chimuka L. Extraction and preconcentration of Cr(VI) from urine using supported liquid membrane. Analytica Chimica Acta 474 (1-2): 59-68, 2002
  9. Cukrowska E , Cukrowski I, Havel J. Application of artificial neural networks for analysis of highly overlapped and disturbed differential pulse polarographic peaks in the region of hydrogen evolution. South African Journal of Chemistry-Suid-Afrikaanse Tydskrif Vir Chemie 53: Art. No. 5 DEC 2000
  10. Cukrowska E , Dube A. Chemical speciation of chromium in various matrices in South African terrestrial water using an optimised adsorptive stripping voltammetric procedure. South African Journal of Chemistry-Suid-Afrikaanse Tydskrif Vir Chemie 54: 1-19 Dec 7 2001