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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 microextraction techniques for analysis of biological samples
Lučaj, Martin ; Vespalcová, Milena (referee) ; Dvořák, Miloš (advisor)
This bachelor thesis deals with the analysis of basic drugs in biological samples by in line coupling of supported liquid membrane (SLM) to capillary electrophoresis (CE). The tITP method was included as an on-line preconcentration step to achieve better detection limits with ammonium acetate as the tITP stacker and acetic acid as the CE background electrolyte. The practical part of the thesis focuses on the optimization of the tITP and the SLM extraction conditions in the analysis of basic drugs in complex biological samples (human urine). The best analytical results were achieved with hydrodynamic injection of ammonium acetate for 15 s and basic drugs for 15 s. The donor was alkalised with 10 mM sodium hydroxide and acceptor was acidified with 10 mM hydrochloric acid. From the results, the in-line coupling of SLM extraction to CE and stacking by tITP is an efficient method allowing direct analysis of complex samples with improved sensitivity of the analytical method.
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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 microextraction techniques for analysis of biological samples
Lučaj, Martin ; Vespalcová, Milena (referee) ; Dvořák, Miloš (advisor)
This bachelor thesis deals with the analysis of basic drugs in biological samples by in line coupling of supported liquid membrane (SLM) to capillary electrophoresis (CE). The tITP method was included as an on-line preconcentration step to achieve better detection limits with ammonium acetate as the tITP stacker and acetic acid as the CE background electrolyte. The practical part of the thesis focuses on the optimization of the tITP and the SLM extraction conditions in the analysis of basic drugs in complex biological samples (human urine). The best analytical results were achieved with hydrodynamic injection of ammonium acetate for 15 s and basic drugs for 15 s. The donor was alkalised with 10 mM sodium hydroxide and acceptor was acidified with 10 mM hydrochloric acid. From the results, the in-line coupling of SLM extraction to CE and stacking by tITP is an efficient method allowing direct analysis of complex samples with improved sensitivity of the analytical method.
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Considerations on electrolysis in electromembrane extraction of basic drugs
Šlampová, Andrea ; Kubáň, Pavel ; Boček, Petr
Electrolysis may significantly affect composition and pH values of non-optimized acceptor solutions and have fatal consequences on quantitative EME results for weak and medium strong analytes. Acceptor solutions consisting of high concentrations of weak acids have therefore been proposed as suitable operational solutions for electromembrane extraction (EME) of selected basic drugs. 500 mM formic acid efficiently eliminated the electrolytically produced OH– ions, offered constant pH and thus long-term EME performance and was easily compatible with subsequent analytical methods. Maximum EME recoveries ranged from 66 to 89% and were constant between 40 and 80 min of EME and no back-extraction of the analytes into donor solutions was observed.
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