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Low-cost microextraction and preconcentration procedures for biomedical applications
Vašátko, Jan ; Diviš, Pavel (referee) ; Dvořák, Miloš (advisor)
This thesis focuses on low-cost microextraction techniques and their application for purification and preconcentration of biological samples, specifically on the experimental study of supported liquid membrane (SLM) extraction. The described microextraction technique uses commercially available filtration plates as the extraction units and allows the extraction of basic drugs from biological samples of urine and blood (in the form of dried blood spots). The experimental part includes the optimization of microextraction conditions of basic drugs from real samples through a SLM coupled in-line to lab-made capillary electrophoresis. The basic optimization of microextraction conditions involved selecting the appropriate organic phase for membrane impregnation (1:1 mixture of ENB and DHE), appropriate agitation speed for sample convection during extraction (1000 rpm), and optimal ratio of donor to acceptor volumes for high preconcentration of the analytes (400:15 µL). After basic optimization, the effect of donor alkalization with NaOH on extraction recovery (ER) was investigated. For all matrices used (saline solution, undiluted human urine samples, human capillary blood eluted from dry blood spots with deionized water), the highest ER values were achieved using a neutral donor and an acidic acceptor. The extraction time (60 minutes) was optimized based on the time profile of the microextraction for 120 minutes. This optimized microextraction method is suitable for the determination of basic drugs in real matrices with sufficient sample clean-up, preconcentration and ER values.
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Coupling of micro-electromembrane extraction to transient capillary isotachophoresis for the analysis of drugs in biological samples
Lučaj, Martin ; Pospíchal,, Jan (referee) ; Dvořák, Miloš (advisor)
The diploma thesis is focused on the development of in-line micro-electromembrane extraction (EME) coupled to capillary electrophoresis (CE) for the analysis of selected drugs in body fluids. Up to now, direct coupling of EME to CE has been demonstrated on diluted river samples only [1]. Although the published set-up has been implemented within a commercial CE it suffers from several drawbacks that can have a negative impact on the analysis of samples with higher complexity. The instrumental arrangement presented in this thesis eliminates these deficiencies. The experimental part is based on the optimization of fundamental extraction and separation conditions for the analysis of model basic drugs (nortriptyline, haloperidol, loperamide) with the use of transient isotachophoresis (tITP) principle. The extraction conditions were optimized for electro-driven transport of basic analytes from complex matrices (urine) through free liquid membrane followed by injection step utilized by electrokinetic supercharging (EKS), which focused target analytes into the CE capillary. Optimized conditions have been applied on blood in the form of dry blood spots, which are highly attractive samples in the current clinical analysis. The repeatability of the measurements was
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Application of polymer membranes in microextraction techniques for analysis of biological samples
Ryšavá, Lenka ; Diviš, Pavel (referee) ; Dvořák, Miloš (advisor)
The thesis presents experimental study on application of various polypropylene membranes (with different thicknesses, porosity and pore size) for direct coupling of membrane microextractions with capillary electrophoresis. No comprehensive study, which describes effect of these membrane parameters on extraction recoveries, was published in the past. Previous scientific works prefer application of 100 µm polypropylene membranes for their easy handling and satisfactory extraction efficiencies. Experimental part includes examination of selected polypropylene membranes as supported liquid membranes in-line coupled to capillary electrophoresis for analysis of basic drugs from complex samples. Membranes with three thicknesses (25, 100 and 170 µm) were tested. The highest extraction recoveries were achieved for the 25µm thick polypropylene membrane. Various pH conditions of donor and acceptor operational solutions were examined for extractions from real complex matrices (urine, plasma). The optimal extraction conditions were 10 mM NaOH as donor phase and 10 mM HCl as acceptor phase. 25µm membranes offer higher extraction recoveries, reduced consumption of organic solvents for membrane impregnation, similar mechanical stability and similar clean-up ability compared to thicker polypropylene membranes.
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Coupling of micro-electromembrane extraction to transient capillary isotachophoresis for the analysis of drugs in biological samples
Lučaj, Martin ; Pospíchal,, Jan (referee) ; Dvořák, Miloš (advisor)
The diploma thesis is focused on the development of in-line micro-electromembrane extraction (EME) coupled to capillary electrophoresis (CE) for the analysis of selected drugs in body fluids. Up to now, direct coupling of EME to CE has been demonstrated on diluted river samples only [1]. Although the published set-up has been implemented within a commercial CE it suffers from several drawbacks that can have a negative impact on the analysis of samples with higher complexity. The instrumental arrangement presented in this thesis eliminates these deficiencies. The experimental part is based on the optimization of fundamental extraction and separation conditions for the analysis of model basic drugs (nortriptyline, haloperidol, loperamide) with the use of transient isotachophoresis (tITP) principle. The extraction conditions were optimized for electro-driven transport of basic analytes from complex matrices (urine) through free liquid membrane followed by injection step utilized by electrokinetic supercharging (EKS), which focused target analytes into the CE capillary. Optimized conditions have been applied on blood in the form of dry blood spots, which are highly attractive samples in the current clinical analysis. The repeatability of the measurements was
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Low-cost microextraction and preconcentration procedures for biomedical applications
Vašátko, Jan ; Diviš, Pavel (referee) ; Dvořák, Miloš (advisor)
This thesis focuses on low-cost microextraction techniques and their application for purification and preconcentration of biological samples, specifically on the experimental study of supported liquid membrane (SLM) extraction. The described microextraction technique uses commercially available filtration plates as the extraction units and allows the extraction of basic drugs from biological samples of urine and blood (in the form of dried blood spots). The experimental part includes the optimization of microextraction conditions of basic drugs from real samples through a SLM coupled in-line to lab-made capillary electrophoresis. The basic optimization of microextraction conditions involved selecting the appropriate organic phase for membrane impregnation (1:1 mixture of ENB and DHE), appropriate agitation speed for sample convection during extraction (1000 rpm), and optimal ratio of donor to acceptor volumes for high preconcentration of the analytes (400:15 µL). After basic optimization, the effect of donor alkalization with NaOH on extraction recovery (ER) was investigated. For all matrices used (saline solution, undiluted human urine samples, human capillary blood eluted from dry blood spots with deionized water), the highest ER values were achieved using a neutral donor and an acidic acceptor. The extraction time (60 minutes) was optimized based on the time profile of the microextraction for 120 minutes. This optimized microextraction method is suitable for the determination of basic drugs in real matrices with sufficient sample clean-up, preconcentration and ER values.
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Application of polymer membranes in microextraction techniques for analysis of biological samples
Ryšavá, Lenka ; Diviš, Pavel (referee) ; Dvořák, Miloš (advisor)
The thesis presents experimental study on application of various polypropylene membranes (with different thicknesses, porosity and pore size) for direct coupling of membrane microextractions with capillary electrophoresis. No comprehensive study, which describes effect of these membrane parameters on extraction recoveries, was published in the past. Previous scientific works prefer application of 100 µm polypropylene membranes for their easy handling and satisfactory extraction efficiencies. Experimental part includes examination of selected polypropylene membranes as supported liquid membranes in-line coupled to capillary electrophoresis for analysis of basic drugs from complex samples. Membranes with three thicknesses (25, 100 and 170 µm) were tested. The highest extraction recoveries were achieved for the 25µm thick polypropylene membrane. Various pH conditions of donor and acceptor operational solutions were examined for extractions from real complex matrices (urine, plasma). The optimal extraction conditions were 10 mM NaOH as donor phase and 10 mM HCl as acceptor phase. 25µm membranes offer higher extraction recoveries, reduced consumption of organic solvents for membrane impregnation, similar mechanical stability and similar clean-up ability compared to thicker polypropylene membranes.
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