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Testing of new electrode arrangements for monitoring of electrochemically oxidisable biologically active organic compounds
Libánský, Milan
Submitted Ph.D. Thesis is focused on the electrochemical characterization and testing of recently developed working electrodes made from pure gold or graphitic carbon particles and electrochemical arrangements. These electrodes are suitable for large screening measurements of various organic compounds. The development of new sensitive voltammetric methods for determination of oxidisable biologically active organic compounds is another aim of this work. To verify its applicability, the array of carbon composite film electrodes integrated in measuring cell system was selected for the development of voltammetric methods for determination of homovanillic acid, vanillylmandelic acid, and indoxyl sulphate. These analytes, which belong to the group of biomarkers of human diseases, were selected for increasing interest in their determination in medical laboratories. Moreover, determination of indoxyl sulphate was coupled to its solid phase extraction from human urine prior to voltammetric determination. Obtained results were compared with measurements of standards with well-established carbon paste electrode. Sputtered (physical vapour deposition method) gold nanostructured film electrodes on treated PTFE substrates and gold nanostructured film electrodes modified with various functional groups on the...
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Voltammetric and amperometric determination of homovanillic, vanillylmandelic, and 5-hydroxyindole-3-acetic acid
Němečková, Anna ; Barek, Jiří (advisor) ; Labuda, Ján (referee) ; Skopalová, Jana (referee)
Presented dissertation thesis is focused on the development of electrochemical methods for the determination of three important tumour biomarkers, namely homovanillic acid (HVA), vanillylmandelic acid (VMA), and 5-hydroxyindole-3-acetic acid (5-HIAA). First part of the study is focused on electrochemical behaviour of these analytes in batch arrangement using differential pulse voltammetry (DPV) at screen-printed carbon electrodes (SPCEs). It has been proved that presented method is sufficiently sensitive for monitoring above mentioned analytes. Moreover, it can be used for determination of HVA and VMA in mixture. Obtained limits of detection (LODs) were 0.24 µmol·L-1 for HVA, 0.06 µmol·L-1 for VMA, and 0.12 µmol·L-1 for 5-HIAA. The requirements to speed up the analysis and at the same time to reduce its price initialized our study of the determination of tested biomarkers in flow systems. Firstly, flow injection analysis with amperometric detection was investigated for the determination of all three biomarkers at the same SPCE, and then an analogous determination of structural more similar pair, HVA and VMA, was performed at a boron doped diamond electrode (BDDE). Obtained LODs of optimized methods were as follows: at SPCE 0.07 µmol·L-1 for HVA, 0.05 µmol·L-1 for VMA, and 0.03 µmol·L-1 for 5-HIAA,...
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Testing of new electrode arrangements for monitoring of electrochemically oxidisable biologically active organic compounds
Libánský, Milan
Submitted Ph.D. Thesis is focused on the electrochemical characterization and testing of recently developed working electrodes made from pure gold or graphitic carbon particles and electrochemical arrangements. These electrodes are suitable for large screening measurements of various organic compounds. The development of new sensitive voltammetric methods for determination of oxidisable biologically active organic compounds is another aim of this work. To verify its applicability, the array of carbon composite film electrodes integrated in measuring cell system was selected for the development of voltammetric methods for determination of homovanillic acid, vanillylmandelic acid, and indoxyl sulphate. These analytes, which belong to the group of biomarkers of human diseases, were selected for increasing interest in their determination in medical laboratories. Moreover, determination of indoxyl sulphate was coupled to its solid phase extraction from human urine prior to voltammetric determination. Obtained results were compared with measurements of standards with well-established carbon paste electrode. Sputtered (physical vapour deposition method) gold nanostructured film electrodes on treated PTFE substrates and gold nanostructured film electrodes modified with various functional groups on the...
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Testing of new electrode arrangements for monitoring of electrochemically oxidisable biologically active organic compounds
Libánský, Milan ; Zima, Jiří (advisor) ; Navrátil, Tomáš (referee) ; Šelešovská, Renáta (referee)
Submitted Ph.D. Thesis is focused on the electrochemical characterization and testing of recently developed working electrodes made from pure gold or graphitic carbon particles and electrochemical arrangements. These electrodes are suitable for large screening measurements of various organic compounds. The development of new sensitive voltammetric methods for determination of oxidisable biologically active organic compounds is another aim of this work. To verify its applicability, the array of carbon composite film electrodes integrated in measuring cell system was selected for the development of voltammetric methods for determination of homovanillic acid, vanillylmandelic acid, and indoxyl sulphate. These analytes, which belong to the group of biomarkers of human diseases, were selected for increasing interest in their determination in medical laboratories. Moreover, determination of indoxyl sulphate was coupled to its solid phase extraction from human urine prior to voltammetric determination. Obtained results were compared with measurements of standards with well-established carbon paste electrode. Sputtered (physical vapour deposition method) gold nanostructured film electrodes on treated PTFE substrates and gold nanostructured film electrodes modified with various functional groups on the...
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