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Modification of nanofibres for extraction in liquid chromatography
Valachovič, Adam ; Šatínský, Dalibor (advisor) ; Chocholouš, Petr (referee)
Department: Department of Analytical Chemistry Candidate: Adam Valachovič Supervisor: doc. RNDr. Dalibor Šatínský, Ph.D. Title of the diploma thesis: Modification of nanofibers for extraction in liquid chromatography The diploma thesis demonstrates the influence of modifications of polymer nanofibers on their extraction properties for extraction in liquid chromatography. Nanofibers represent a potential sorbent for extraction methods due to their large surface area, which leads to increased capacity of extraction. Another advantage of nanofibers is the possibility to modify their surface resulting in various nanofibers with different extraction properties. In this thesis, the modifications were performed by coating polypropylene nanofibers with a polydopamine layer. The polymerization solution was pumped through a column, in which the nanofibers were placed, using a peristaltic pump connected to the column by a system of tubes. An on-line SPE HPLC method was developed to determine the extraction properties of the modified nanofibers. Chlorogenic acid was chosen as the model analyte, because its extraction is affected by the polydopamine layer. The key parameters of the coating process were optimized, including the weight of the nanofibers, the concentration of dopamine in the polymerization...
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Spectrophotometric determination of chlorhexidine in mouthwash employing Lab-In-Syringe automated ion-pair extraction and back-extraction
Řeháková, Pavla ; Horstkotte, Burkhard (advisor) ; Chocholouš, Petr (referee)
Charles University Faculty of Pharmacy in Hradec Králové Department of Analytical Chemistry Candidate: Pavla Řeháková Supervisor: Dr. Burkhard Horstkotte, Ph.D., M.Sc. Consultant: doc. PharmDr. Hana Sklenářová, Ph.D. Title of the diploma thesis: Spectrophotometric determination of chlorhexidine in mouthwash employing Lab-In-Syringe automated ion-pair extraction and back-extraction In this work, a magnetic stirring-assisted dispersive liquid-liquid micro-extraction (MSA-DLLME) automated by the Lab-In-Syringe technique is presented. MSA-DLLME is based on mixing the sample and an immiscible solvent by the action of a magnetic stirrer for the dispersion of the solvent into fine droplet to enhance the extraction process. In Lab-In-Syringe, the magnetic stirrer is placed inside a syringe void, which is used as extraction chamber. To allow the use of an extraction solvent lighter than water, the syringe was turned upside down in this work. This method was designed for the determination of chlorhexidine in commercial mouthwash samples. To allow the extraction of chlorhexidine, an ion-pair complex with the reagent methyl orange needed to be formed. After the extraction into an organic solvent, the aqueous solution was exchanged and the analyte was back-extracted into an acidic aqueous acceptor to yield...
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Application of Raman spectrometry for identification of organic substances and their differentiation in real samples
Kubulková, Barbora ; Sklenářová, Hana (advisor) ; Chocholouš, Petr (referee)
Charles University Faculty of Pharmacy in Hradec Králové Department of Analytical Chemistry Candidate: Barbora Kubulková Supervisor: doc. PharmDr. Hana Sklenářová, Ph.D. Title of diploma thesis: Application of Raman spectrometry for identification of organic substances and their differentiation in real samples The objectives of the thesis were to perform analysis and identification of specific pharmaceutical products using Raman spectrometry. The analyzed products were bulk- produced pharmaceuticals. The samples, common sortiment in pharmacy, were divided into the groups based on the therapeutic class and dosage form. The samples included antipyretics in the form of hot-drink preparations, joint nutrition in the form of granulates and tablets, vitamins and analgesics in solid dosage form -tablets. Also, structurally similar substances were compared. Raman spectrometry is contactless analytical method, which allowed us to measure the samples of uncoated tablets via compliance packaging - blisters. The pharmaceuticals in the dosage form of granulates were analyzed directly or dissolved in the distilled water and analyzed as solutions. The spectra of the analyzed samples were compared with spectra of the respective active substances.
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Interactions of tamarixetin and isorhamnetin with copper
Lomozová, Zuzana ; Karlíčková, Jana (advisor) ; Chocholouš, Petr (referee)
Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Botany Candidate: Zuzana Lomozová Supervisor: PharmDr. Jana Karlíčková, Ph.D. Title of Thesis: Interactions of tamarixetin and isorhamnetin with copper Keywords: tamarixetin, isorhamnetin, chelation, reduction, copper, bathocuproine, hematoxylin Copper is a biogenic trace element important for proper function of human organism. It is an essential part of several enzymes and is involved in metabolic processes in the body. Excess or lack of serum copper can lead to pathological conditions. Copper chelating agents are used to treat copper toxic effects. Flavonoids are polyphenolic substances belonging to secondary metabolites of various plants. They are part of the human diet and have a positive impact on our health. They exhibit antioxidant and anti-inflammatory effects and are able to chelate transient metals, especially iron and copper. Chelation therapy is currently used in Wilson's disease in which copper is overloaded. In the future, the chelating effects of flavonoids could be used to treat neurodegenerative diseases, cardiovascular diseases or cancer. In this diploma thesis, interactions of two flavonoids (namely tamarixetin and isorhamnetin) with copper ions in different buffers were tested....
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Development of on-line SPE HPLC method for determination of ochratoxin A in Tokaj wines
Uhrová, Adéla ; Šatínský, Dalibor (advisor) ; Chocholouš, Petr (referee)
Charles University Faculty of Pharmacy in Hradec Králové Department of Analytical Chemistry Candidate: Bc. Adéla Uhrová Supervisor, consultant: Doc. RNDr. Dalibor Šatinský, Ph.D. Title of Diploma Thesis: Development of on-line SPE HPLC method for determination of ochratoxin A in Tokaj wines This diploma thesis deals with the optimization and validation of chromatographic method for determination of ochratoxin A in Tokaj wine with subsequent application on real samples. A high- performance liquid chromatography method with fluorescence detection using on-line extraction by column switching has been developed. 50µl of sample was injected directly in the extraction column, where at 1st minute the analyte was extracted on the Ascentis® Express RP-Amide precolumn in the presence of a mobile phase of 40% MeOH in 0.5% aqueous acetic acid. After the extraction, the valve was switched and the extracted substances were separated on a YMC Triart C18 ExRS analytical column. The separation was carried out under gradient elution with an initial acetonitrile ratio of 45% in the mobile phase, which reached a concentration of 80% in the 5th minute. Fluorimeter detection was optimized for excitation and emission wavelengths ʎEx 335 nm and ʎEm 463 nm. In the last part of the work, ochratoxin A was analyzed in real...
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Study of nanofibers as sorbents for solid phase extraction using sequential injection analysis.
Štefčáková, Natália ; Horstkotte Šrámková, Ivana (advisor) ; Chocholouš, Petr (referee)
Charles University Faculty of Pharmacy in Hradec Králové Department of Analytical Chemistry Candidate: Natália Štefčáková Supervisor: PharmDr. Ivana Horstkotte Šrámková, Ph.D. Title: Study of nanofibers as sorbent for solid phase extraction using sequential injection analysis Various types of nanofibres were studied in the sequential injection analysis (SIA) system, where nanofibers were used as potential sorbents for solid phase extraction. Six types of nanofibers were tested in this thesis- polycaprolactone/polyvinylidene fluoride (PCL/PVDF), polyamide (PA 6), polystyrene (PS), polyvinylidene fluoride (PVDF), polyacrylonitrile (PAN) and polyethylene (PE). These nanofibers were produced by the electrospinning method. Substances with different physico-chemical properties were selected: bisphenol A and antibiotics oxytetracycline, amoxicillin, sulfadiazine and sulfathiazole. The nanofibers were placed in a 3D printed holder plugged into the SIA system. UV spectrophotometry was used as a detection technique. In this diploma thesis, parameters such as retention of substances on a given type of nanofibres, capacity of nanofibres and optimization of parameters for extraction of bisphenol A (sample volume, type, volume, concentration of eluent) were monitored and the 3D holder was tested as an...
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Automation of determination using different types of luciferase
Dobrovolná, Denisa ; Sklenářová, Hana (advisor) ; Chocholouš, Petr (referee)
Charles University Faculty of Pharmacy in Hradec Králové Department of Analytical Chemistry Candidate: Denisa Dobrovolná Supervisor: Doc. PharmDr. Hana Sklenářová, Ph.D. Consultant: prof. Manuel Miró Title of diploma thesis: Automation of determination using different types of luciferase The aim of this diploma thesis was optimization the assay conditions by using sequential injection analysis. Two types of luciferase were used to optimize the method-type one and type two. Two different flow cells with different volume and optical path were used - the first flow cell with volume of 100 µl and 3x3 mm optical path and the second flow cell with volume of 120 µl and 5x5 mm optical path. The parameters of measurement were optimized - especially flow rate, accumulation time, cycle time and detector sensitivity. The method was first tested using an indirect luminal system to optimize fluorescence detector settings and reaction conditions. The best results were obtained with the flow cell with the volume of 120 µl and 5x5 mm optical path. Better measurement repeatability was observed using this flow cell. The measurement optimization continued using this flow cell by determining type one - non-secreted luciferase, and subsequently type two - secreted luciferase. Due to unsatisfactory repeatability and...
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Testing of stability of antivirotic drugs using ultra-high performance liquid chromatography
Pavlasová, Pavlína ; Kočová Vlčková, Hana (advisor) ; Chocholouš, Petr (referee)
Charles univerzity Fakulty of Pharmacy in Hradec Králové Department od Analytical Chemistry Candidate: Pavlína Pavlasová Supervisor: RNDr. Hana Kočová Vlčková, Ph.D. Title of thesis: Testing of stability of antivirotic drugs using ultra-high performance liquid chromatography. This thesis is concerned with determining the stability of five antiviral drugs (ledipasvir, sofosbuvir, tenofovir and the monoester and diester of tenofovir) under various temperature conditions. The study employed ultra-high performance liquid chromatography with a photodiode array detector detection at 259 nm. The tested antiviral drugs are new medicinal products used in treating serious diseases such as AIDS and hepatitis C. Two types of stability were tested: short-term and long-term. The short-term stability of the substances was tested in acetonitrile and methanol at 4 řC and 22 řC for 24 hours. The long- term stabilities of sofosbuvir and the monoester and diester of tenofovir in 50 % acetonitrile, ledipasvir in 100 % acetonitrile and tenofovir in water were determined while maintaining the substances at three temperatures in the medium: - 20 řC, 4 řC and 22 řC for a period of 28 days. In addition the substances were tested in phosphate buffers for 90 days for storage at - 20 řC. The storage conditions and the time...
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On-line solid phase extraction using complexing reagents
Kopinská, Daniela ; Chocholouš, Petr (advisor) ; Horstkotte Šrámková, Ivana (referee)
Charles University Faculty of Pharmacy in Hradec Králové Department of Analytical chemistry Candidate: Daniela Kopinská Supervisor: PharmDr. Petr Chocholouš, Ph.D. Title of the diploma thesis: On-line solid phase extraction using complexing reagents Following diploma thesis was focused on testing of conditions for zinc ions analysis by solid phase extraction using sequential injection analysis system (SIA). The thesis includes introduction to solid phase extraction and SIA system. To optimize the method, concentrations of 0.1 - 100.0 µmol/l zinc sulfate were used. Also, testing of elution solutions with various concentrations of acetonitrile and derivatization reagent 4- (2-Pyridylazo) resorcinol (PAR) was performed. Three columns with sorbents C18, CN and C8 of dimensions 10 x 1.5 mm were tested. The carrier and sample diluent was 0.1 mol/l ammonium acetate pH 6. The aim was to extract and determine zinc ions at the lowest concentrations possible. Detection was performed at 430, 490 and 630 nm by using a spectrophotometric detector. The most suitable column for analysis was C8 (10 x 1.5 mm. The most suitable eluent was 50% ACN. The applicable concentration of PAR reagent was 5 µmol/l. Tested parameters were calibration range 0.5 - 5.0 µmol/l and method repeatability.
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