Faculty of Natural and Agricultural Sciences
School of Physical Sciences
Department of Chemistry
Selected Highlights from Research Findings
New designs for electrochemical sensors proposed. Fullerenes C60 and C70 and their derivatives were used for the first time as new chiral selectors for the design of enantioselective, potentiometric membrane electrodes. Monocrystalline diamond paste based electrodes were designed for bioanalysis due to the high biocompatibility of the diamond and also to the enhanced physical properties of the monocrystalline structure. The first diamond paste electrodes were amperometric ones, and three types of diamond (1 natural and 2 synthetic types) were utilized. These amperometric electrodes were used for the assay of cations (Fe(II), Fe(III), Cr(III), Cr(VI), Pb(II), Ag(I)), an anion (I-), L- and D-pipecolic acid, creatine and creatinine in different matrices (biological, pharmaceutical, environmental). All the monocrystalline diamond paste based sensors proved to enhance selectivity and sensitivity for the proposed analytes versus those obtained using glassy carbon and carbon paste electrodes.
Contact person: Dr R-I Stefan.
In certain areas the real time monitoring of natural waters is important. Process analysers in process analytical science with sequential injection systems form an ideal tool in this regard and a number of systems for various substances have been developed. A new computer program, LABVIEW, has successfully been introduced to fully control process analytical sequential and flow injection systems. The highlight of these systems is that it is possible to do fully automated simultaneous titration of both carbonate and bicarbonate. Sequential injection systems have also been successfully employed together with chemometrics in assays for multicomponent analysis.
Contact person: Prof JF van Staden.
Together with Dr Stefan, multicomponent analysis was performed for the simultaneous assay of enantiomers of methotrexate and carnitine as well as of creatine and creatinine using sequential injection analysis/sensors systems. The utilization of the enantiomer selective sensors for high throughput screening of chiral amino acids and drugs is an innovation. The system permits the faster and simultaneous testing of new chiral selectors (up to 16 at once), as well as the screening of chiral drugs and creatinine and creatine. Speciation was done for the Br species using sequential injection analysis. Process sequential injection titration systems were designed and implemented for a number of substances.
Contact person: Prof JF van Staden.
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