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Electrochemical behavior of some purine derivatives on carbon based electrodes

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Câmpean A., Tertiş M., Săndulescu R.

Open Chemistry

2011

vol. 9

issue 3

466-473

The electrochemical behaviour of three purine derivatives was investigated by cyclic voltammetry on different electrode materials: glassy carbon in native form and electrochemically activated, carbon paste electrode unmodified or modified with 1, 4-benzoquinone. The preliminary study obtained on solid electrodes was extended to graphite based planar screen-printed electrodes, unmodified and modified with multi-wall carbon nanotubes, or cobalt phthalocyanine. The influence of some experimental parameters (pH, scan rate, concentration and electrolytic medium) on the electrochemical behaviour of these alkaloids was also examined. The electrochemical oxidation of purine derivatives is an irreversible and diffusion controlled process, proved by the linear dependence between the peak potentials and the logarithm of scan rates and between the anodic peak current and the square root of scan rate.

Voltammetric determination of some alkaloids and other compounds in pharmaceuticals and urine using an electrochemically activated glassy carbon electrode

100%

Câmpean A., Tertiş M., Săndulescu R.

Open Chemistry

2011

vol. 9

issue 4

688-700

Electrochemical behaviour of some alkaloids, namely: caffeine, aminophylline, theophylline, codeine phosphate and papaverine hydrochloride, that are in solution in various combinations or in the presence of other compounds contained in pharmaceuticals or in real samples (urine) was investigated using cyclic voltammetry (CV), square-wave voltammetry (SWV) and differential pulse voltammetry (DPV) on electrochemically activated glassy carbon electrode. [...] The proposed electroanalytical methods were successfully applied in the simultaneous determination of these alkaloids in different combination or in the presence of other compounds. The great part of these combinations can be analyzed simultaneously because they practically do not interfere. The electrochemical test methods attempted to detect the presence of alkaloids in urine samples collected from subjects who consumed coffee (caffeine), and from a patient under treatment with Miofilin® (aminophylline). Urine samples were determined after filtration, without prior dilution and after dilutiion with acetate buffer at pH 4.5. Best results were obtained using DPV performed on electrochemically activated glassy carbon electrode. Thus in samples taken from subjects who drink coffee the caffeine concentration detected was 6.21×10−7 mol L−1 in the first sample and 7.77×10−7 mol L−1 in the second sample, while aminophylline concentration detected was 1.15×10−7 mol L−1.

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2 Open Chemistry

2 2011

2 Câmpean A.

2 Săndulescu R.

2 Tertiş M.

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Electrochemical behavior of some purine derivatives on carbon based electrodes

Voltammetric determination of some alkaloids and other compounds in pharmaceuticals and urine using an electrochemically activated glassy carbon electrode