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Continuous monitoring of anthraquinone-based anticancer drugs by amperometric technique
Skalová, Štěpánka ; Fischer, J. ; Barek, J. ; Navrátil, Tomáš ; Krejčí, J. ; Kučerová, R. ; Vyskočil, V.
This contribution is focused on the development of electroanalytical methods for the monitoring of anthraquinone-based anticancer drugs in physiological solution by combination of liquid-flow system and dialysis catheter, possibly inserted into blood circulation of patients. For this purpose, amperometric detection with dual glassy carbon electrode was developed and derivate of these drugs, anthraquinone-2-sulphonate, was used as a model compound. Two different flow rates of carrier solution (physiological solution) were tested (specifically, 1 and 5 mu L min(-1)) and the dependence of peak currents of anthraquinone-2-sulphonate on its concentration was verified
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Construction and Application of Flow Amperometric Biosensor Based on Enzymatic Reactor for Determination of Choline
Tvorynska, Sofiia ; Barek, J. ; Josypčuk, Bohdan
In this contribution, a novel fast, simple and stable biosensor with the enzymatic reactor based on choline oxidase (ChOx) was developed and applied for the determination of choline using flow injection analysis with amperometric detection. The preparation of the reactor is based on the covalent immobilization of ChOx with glutaraldehyde to mesoporous silica powder (SBA-15) previously covered by NH2-groups. The experimental parameters affecting the sensitivity and stability of the biosensor were optimized. The proposed biosensor with the newly developed ChOx-based reactor possesses good repeatability, reproducibility, long-term stability, and reusability. It was successfully applied for the determination of choline in commercial pharmaceuticals.
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Voltametrické stanovení pálivosti chilli paprik na elektrodě ze skelného uhlíku modifikované fosfolipidy
Skopalová, J. ; Rajcová, A. ; Vokounová, D. ; Navrátil, Tomáš
Kapsaicin je přírodní alkaloid vyskytující se v plodech chilli paprik, které patří k nejdůležitějším a nejrozšířenějším kořením. Za jejich popularitou stojí významné organoleptické vlastnosti (typická pálivá chuť), antioxidační či antimikrobiální účinky. Pálivost chilli paprik je hlavním důvodem jejich konzumace a z pohledu konzumenta představuje jednu z jejich nejdůležitějších charakteristik. Od toho se proto odvozuje potřeba tuto charakteristiku kvantifikovat. Míra pálivosti přímo souvisí s obsahem kapsaicinu a jemu podobných látek (kapsaicinoidů) v paprikách. Kromě potravinářství nachází kapsaicin své užití i v lesnictví (zemědělství) jako ochrana před okusem stromů zvěří.
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Pilot Experiments With a Micro-Volume Voltammetric Cell for the Determination of Electrochemically Reducible Organic Compounds
Skalová, Štěpánka ; Barek, J. ; Rodrigues, J. A. ; Goncalves, L.M. ; Navrátil, Tomáš ; Vyskočil, V.
A new micro-volume voltammetric cell for analysis of small volumes\nof electrochemically reducible organic compounds was developed\nand tested. The sample (20-100 mu L) is placed in a narrow glass tube\nwith an agar membrane at the bottom and the working electrode is\nimmersed into the sample. The agar membrane, as anion permeable\nlayer, electrically connects the workin g e lectrode immersed in the\nanalysed sample in the glass tube with a large-volume compartment\n(20 mL) filled with Britton-Robinson buffer, where conventional nonminiaturized\nreference and auxiliary electrodes are placed. The system\nwas tested using a polished silver solid amalgam electrode\n(p-AgSAE) as a working electrode. Sodium anthraquinone-2-sulfonate\nwas used as a model compound because it is intended to use this\nsystem to monitor electrochemically reducible organic compounds.
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