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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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Voltammetric Determination of Chili Peppers Pungency using Phospholipid Modified Glassy Carbon Electrode\n
Skopalová, J. ; Rajcová, A. ; Vokounová, D. ; Navrátil, Tomáš
The aim of this study was to develop a simple method for evaluation of the pungency in chili peppers with a glassy carbon electrode modified using phospholipid membrane prepared from asolectin. For these purposes cyclic voltammetry (CV) and differential pulse voltammetry (DPV) have been used. A few different methods have been tested: direct method, transfer method on unmodified and modified electrode, using standard addition method as well as calibration curve method. A statistically significant correlations with the results of the reference HPLC method have been found in case of voltammetric methods, especially in DPV with asolectin modified electrode.
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Application of a Micro-Volume Voltammetric Cell for Determination of Doxorubicin Hydrochloride
Skalová, Štěpánka ; Navrátil, Tomáš ; Barek, J. ; Vyskočil, V.
Doxorubicin is an anticancer drug, which is used for treatment of various cancer types. It contains a quinone structure, similarly as some other drugs belonging to the same category (e.g., daunorubicin and epirubicin). Its monitoring can lead to optimization of individual patient dosages and increase chances for recovery of patients. A micro-volume voltammetric cell and differential pulse cathodic stripping voltammetry have been used for determination of doxorubicin hydrochloride. A volume of used sample was 50 microL. Limit of detection was 0.39 micromol L-1. An applicability of this method was verified on samples of drinking water and of human urine.
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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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