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A Novel Sensor Based on Carbon Paste Electrode Modified with Polypyrrole/Multi-walled Carbon Nanotubes for the Electrochemical Detection of Cytostatic Drug Rapamycin |
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| Authors: | Ivana Zrinski Sanja Martinez Astrid Ortner Anchalee Samphao Janez Zava?nik Kurt Kalcher Eda Mehmeti |
| Institution: | 1. University of Zagreb, Department of Electrochemistry, Faculty of Chemical Engineering and Technology, Maruli?ev Trg 19, 10000 Zagreb, Croatia
Institute of Chemical Technology of Inorganic Materials, Johannes Kepler University Linz, Altenberger Str. 69, 4040 Linz, Austria;2. University of Zagreb, Department of Electrochemistry, Faculty of Chemical Engineering and Technology, Maruli?ev Trg 19, 10000 Zagreb, Croatia;3. Institute of Pharmaceutical Sciences, Karl-Franzens University Graz, Schubertstrasse 1, Graz A, 8010 Austria;4. Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Ubon Ratchathani University, Ubon Ratchathani, 34190 Thailand;5. Department for Nanostructured Materials, Jo?ef Stefan Institute, Jamova 39, Ljubljana, 1000 Slovenia;6. Karl-Franzens University of Graz, Institute of Chemistry-Analytical Chemistry, Universitätsplatz 1/I, A-8010 Graz, Austria |
| Abstract: | The electrocatalytic oxidation of rapamycin, one of the most studied immunosuppressant, cancer-preventing drug, is investigated for the first time on the surface of the modified carbon paste electrode prepared by incorporating multi-walled carbon nanotubes (MWCNTs) and conductive polymer pyrrole using differential pulse voltammetry (DPV). Rapamycin exhibited a well-defined oxidation peak at +1.1 V (versus Ag/AgCl) in Briton Robinson buffer solution with a pH 4.0. Effect of the most important experimental parameters was optimized and obtained signals are linear to the concentration of rapamycin in the range from 0.1 to 20 μM with 0.06 μM limit of detection. The repeatability is calculated as ±2 % and the reproducibility as ±5 %. The possible interfering compounds were tested showing negligible effect and the sensor was successfully applied for the determination of rapamycin in commercial pharmaceutical formulations with obtained recoveries in the range from 98 % to 102 %. |
| Keywords: | rapamycin differential pulse voltammetry modified carbon paste electrode electrochemical oxidation |