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Utilization of potential programs in flow electrochemical determination of biologically active organic compounds
Bavol, Dmytro
9 Abstract In this Ph.D. thesis possibilities of using our proposed potential programs for a multiple-pulse amperometry and a fast scan differential pulse voltammetry in combination with flow systems are presented. The development of new sensitive amperometric and voltammetric methods for the determination of oxidisable biologically active organic compounds is another aim of this work. In the first part of the work, the flow injection system and multiple-pulse amperometric detection were employed to develop and optimize a simple, low-cost, and rapid method for the simultaneous determination of natural and synthetic antioxidants. This technique involves the application of an appropriate potential waveform consisting of a suitable sequence of pulses on a single working electrode, thus allowing distinguish the analytes in a mixture with no need of separation. Conditions for the determination of antioxidants and modelling of the potential program were tested and studied, respectively. Second part of the work describes and characterizes the application of the fast scan differential pulse voltammetry (FSDPV) in combination with the flow systems. FSDPV is the electroanalytical technique that use high scan rate to record voltammograms within several milliseconds and ensures high temporal resolution. This technique...
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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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Utilization of potential programs in flow electrochemical determination of biologically active organic compounds
Bavol, Dmytro
9 Abstract In this Ph.D. thesis possibilities of using our proposed potential programs for a multiple-pulse amperometry and a fast scan differential pulse voltammetry in combination with flow systems are presented. The development of new sensitive amperometric and voltammetric methods for the determination of oxidisable biologically active organic compounds is another aim of this work. In the first part of the work, the flow injection system and multiple-pulse amperometric detection were employed to develop and optimize a simple, low-cost, and rapid method for the simultaneous determination of natural and synthetic antioxidants. This technique involves the application of an appropriate potential waveform consisting of a suitable sequence of pulses on a single working electrode, thus allowing distinguish the analytes in a mixture with no need of separation. Conditions for the determination of antioxidants and modelling of the potential program were tested and studied, respectively. Second part of the work describes and characterizes the application of the fast scan differential pulse voltammetry (FSDPV) in combination with the flow systems. FSDPV is the electroanalytical technique that use high scan rate to record voltammograms within several milliseconds and ensures high temporal resolution. This technique...
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Voltammetric Determination of Tumor Biomarkers using Flow Injection Analysis with Amperometric Detection
Němečková-Makrlíková, Anna ; Matysik, F.-M. ; Navrátil, Tomáš ; Barek, J. ; Vyskočil, V.
Three tumor biomarkers (homovanillic acid, vanillylmandelic acid, and 5-hydroxyindole-3-acetic acid) have been determined by flow injection analysis with amperometric detection at screen-printed carbon electrodes in optimum medium of Britton-Robinson buffer (0.04 mol l(-1), pH = 2.0). Dependences of the peaks current on the concentration of biomarkers were linear in the tested concentration region from 0.05 to 100 mu mol l(-1), with the limits of detection of 0.065 mu mol l(-1) for homovanillic acid, 0.053 mu mol l(-1) for vanillylmandelic acid, and 0.033 mu mol l(-1) for 5-hydroxyindole-3-acetic acid (calculated from heights), and 0.024 mu mol l(-1) for homovanillic acid, 0.020 mu mol l(-1) for vanillylmandelic acid, and 0.012 mu mol l(-1) for 5-hydroxyindole-3-acetic acid (calculated fromareas), respectively.
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Utilization of potential programs in flow electrochemical determination of biologically active organic compounds
Bavol, Dmytro ; Dejmková, Hana (advisor) ; Josypčuk, Bohdan (referee) ; Metelka, Radovan (referee)
9 Abstract In this Ph.D. thesis possibilities of using our proposed potential programs for a multiple-pulse amperometry and a fast scan differential pulse voltammetry in combination with flow systems are presented. The development of new sensitive amperometric and voltammetric methods for the determination of oxidisable biologically active organic compounds is another aim of this work. In the first part of the work, the flow injection system and multiple-pulse amperometric detection were employed to develop and optimize a simple, low-cost, and rapid method for the simultaneous determination of natural and synthetic antioxidants. This technique involves the application of an appropriate potential waveform consisting of a suitable sequence of pulses on a single working electrode, thus allowing distinguish the analytes in a mixture with no need of separation. Conditions for the determination of antioxidants and modelling of the potential program were tested and studied, respectively. Second part of the work describes and characterizes the application of the fast scan differential pulse voltammetry (FSDPV) in combination with the flow systems. FSDPV is the electroanalytical technique that use high scan rate to record voltammograms within several milliseconds and ensures high temporal resolution. This technique...
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Development of electroanalytical methods for detection of cholesterol and 7-dehydrocholesterol
Benešová, Lenka ; Schwarzová, Karolina (advisor) ; Dejmková, Hana (referee)
The aim of this Thesis is development of electroanalytical methods for determination of cholesterol and 7-dehydrocholesterol on boron doped diamond electrodes based on electrochemical oxidation of products of acid-induced dehydration reaction. Two approches have been applied, relying on their detection in 0,1 mol.l-1 perchloric acid in acetonitril containing variable water content 0,43 % - 40 %. Cyclic voltammetry revealed substantial difference in oxidation peak pontecials for 7-dehydrocholesterol (+850 mV) and cholesterol (+1500 mV) in 0,1 mol.l-1 perchloric acid in acetonitrile containing 5 % of water. The limit of detection using differential pulse voltammetry were 6,19 µmol.l-1 a 19,2 µmol.l-1 for a mixture of 7-dehydrocholesterol and cholesterol, respectively. For flow injection analysis with amperometric detection (FIA-AD) the water content in run buffer, detection potencial and the distance between the capillary outlet and electrode surface in wall-jet arrangement of amerometric flow-through detection cell were optimized. Achieved detection limits are in range of 0,61 - 3,43 µmol.l-1 depending on the detection potencial and water concent in the run buffer. The developed FIA-AD method was used for determination of a model mixture solution of 7- dehydrocholesterol and cholesterol. Key words...
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Voltammetric Determination of Tumor Biomarkers using Flow Injection Analysis with Amperometric Detection
Makrlíková, Anna ; Matysik, F.-M. ; Barek, J. ; Vyskočil, V.
Three tumor biomarkers (homovanillic acid, vanillylmandelic acid,\nand 5-hydroxyindole-3-acetic acid) have been determined by flow\ninjection analysis with amperometric detection at screen-printed\ncarbon electrodes in optimum medium of Britton-Robinson buffer\n(0.04 mol l-1, pH = 2.0). Dependences of the peaks current on the\nconcentration of biomarkers were linear in the tested concentration\nregion from 0.05 to 100 mu mol l-1, with the limits of detection of\n0.065 mu mol l-1 for homovanillic acid, 0.053 mu mol l-1 for vanillylmandelic\nacid, and 0.033 mu mol l-1 for 5-hydroxyindole-3-acetic acid (calculated\nfrom heights), and 0.024 mu mol 1-1 for homovanillic acid,\n0.020 mu mol l-1 forvanillylmandelic acid, and 0.012 mu mol l-1 for 5-hydroxyindole-3-acetic acid (calculated from areas), respectively.
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Determination of Nadroparine in Fraxiparine injection solution using flow techniques of anlysis
Miklošinová, Aneta ; Hraníček, Jakub (advisor) ; Křížek, Tomáš (referee)
This thesis was focused on a determination of nadroparin using sequential injection analysis and flow injection analysis with fluorimetric and spectrophotometric detection. The principle of determination was based on the interaction of nadroparin with phenothiazine dye. Methylene blue was used as phenothiazine dye. The determination was performed on a laboratory made FIA instrument and on the commercial SIA instrument. Optimal conditions for SIA were concentration of dye 6 ∙ 10-5 mol dm-3 , injected volume 100 µl, flowrate 1,5 ml min-1 , for FIA: concentration of dye 3 ∙10-5 mol dm-3 flowrate 2 ml ∙ min-1 , injected volume= 100 µl, for fluorimetric detection was sensivity of the detector 1000 V, Emission was measured by 2 nm and excitation wavelenght 621 nm. For spectrophotometric detection, absorbance was detected at the absorption maximum wavelength. Repeatability ranged from 2.01 to 2.85%. The limit of detection for FIA was 0.05-0.09 IU ml-1 , for SIA were limits of detection in range 0,25 - 1,63 IU ml-1 , limits of quantification in range 0,83 - 5,44 and linear range was from 0,5 - 20 IU ml-1 . The limits of detection, limits of determination and the linear range could be corrected for the SIA by the injected volume of phenothiazine dye.
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The Flow Injection Analysis of Procaine and Sulfamethoxazole with Spectrophotometric Detection
Baptistová, Adéla ; Nesměrák, Karel (advisor) ; Červený, Václav (referee)
A derivatization reaction, based on a copulation reaction of diazonium salt of an analyte with a reagent (1-aminonaphthalene or NEDA) producing colour, spectrophotometrically detectable product, has been used for determination of two analytes (procain hydrochloride, sulfamethoxazole) containing amino group in the molecule. The conditions of batch spectrophotometric determination were studied. It was found, that the batch determination is applicable only for procain hydrochloride analysis, because sulfamethoxazole gives time-unstable colour product. FIA arrangement was proposed and effects of selected parameters were optimized using two levels factorial design. The calibration dependences were measured for both analysis with both reagents, and subsequently were applied on determination of analytes in medical forms. Key words: diazotization, flow injection analysis, procaine, spectrophotometry, sulfamethoxazole
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