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Characterization of coloid particles by excited-state proton transfer with advanced fluorescence techniques
Kotouček, Jan ; Mravec, Filip (referee) ; Pekař, Miloslav (advisor)
The deprotonation characteristics of fluorescent probes -naphthol and 8-hydroxypyrene-1,3,6-trisulphonic acid (HPTS) were studied in this diploma thesis, using steady-state and time-resolved fluorescence spectroscopy. Two cationic surfactants, Septonex and cetyltrimethylammonium bromide (CTAB), were studied. These surfactants were measured in the complex with hyaluronan (1.75 MDa, 1 MDa and 300 kDa). Steady-state fluorescence was used for determination of critical aggregation concentration of each surfactant and pKa*. Time-resolved fluorescence decays were used to calculate the average lifetimes and the deprotonation constants of naphthol and HPTS. The measurement with hyaluronan were compared with the polystyrenesulfonate (PSS) – surfactant system. The effect of hydration shell of hyaluronan on hyaluronan – surfactant complex formation results from the comparison of above mentioned systems. Large differences were found in the deprotonation characteristic between surfactants and even between individual molecular weights of hyaluronan. The measurement shows that the hydration shell is located near to the dissociated carboxyl groups of hyaluronan chain, where the interaction with the positively charged surfactants occurs. Furthermore, the aggregation number of Septonex was determined by quenching of pyrene using cetylpyridinium chloride (CPC) as a quencher. The aggregation number for 20 mM Septonex solution was determined as a value of 104 molecules. CPC was used for confirmation of the localization of -naphthol in the micelles of CTAB and polymer – CTAB, respectively.
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Fluorescence in hydrophilic polymers research
Kotouček, Jan ; Pilgrová, Tereza (referee) ; Venerová, Tereza (advisor)
This bachelor thesis deals with the use of fluorescence in the study of hydrophilic polymers such as polyvinylpyrrolidone, carboxymethylcellulose, bovine serum albumin, and hyaluronan. The first measurement was a fluorescence intensity of the anionic form of 3-hydroxy naphtholic acid which undergoes an intramolecular proton transfer in the excited state then the steady-state fluorescence anisotropy of 3-hydroxy naphtholic acid and also the lifetime of the fluorescent probe. The measured data were evaluated in terms of interaction of the fluorescence probe with hydration shell of polymer in an aqueous environment by determination of a binding constant of the system, polymer - fluorescent probe. The interaction between anionic form of the probe with polymer was found in BSA, PVP and CMC systems. There was no interaction of fluorescent probe with hydration shell of hylauronan due to charge repulsion between the probe and hyaluronan.
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Characterization of coloid particles by excited-state proton transfer with advanced fluorescence techniques
Kotouček, Jan ; Mravec, Filip (referee) ; Pekař, Miloslav (advisor)
The deprotonation characteristics of fluorescent probes -naphthol and 8-hydroxypyrene-1,3,6-trisulphonic acid (HPTS) were studied in this diploma thesis, using steady-state and time-resolved fluorescence spectroscopy. Two cationic surfactants, Septonex and cetyltrimethylammonium bromide (CTAB), were studied. These surfactants were measured in the complex with hyaluronan (1.75 MDa, 1 MDa and 300 kDa). Steady-state fluorescence was used for determination of critical aggregation concentration of each surfactant and pKa*. Time-resolved fluorescence decays were used to calculate the average lifetimes and the deprotonation constants of naphthol and HPTS. The measurement with hyaluronan were compared with the polystyrenesulfonate (PSS) – surfactant system. The effect of hydration shell of hyaluronan on hyaluronan – surfactant complex formation results from the comparison of above mentioned systems. Large differences were found in the deprotonation characteristic between surfactants and even between individual molecular weights of hyaluronan. The measurement shows that the hydration shell is located near to the dissociated carboxyl groups of hyaluronan chain, where the interaction with the positively charged surfactants occurs. Furthermore, the aggregation number of Septonex was determined by quenching of pyrene using cetylpyridinium chloride (CPC) as a quencher. The aggregation number for 20 mM Septonex solution was determined as a value of 104 molecules. CPC was used for confirmation of the localization of -naphthol in the micelles of CTAB and polymer – CTAB, respectively.
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Fluorescence in hydrophilic polymers research
Kotouček, Jan ; Pilgrová, Tereza (referee) ; Venerová, Tereza (advisor)
This bachelor thesis deals with the use of fluorescence in the study of hydrophilic polymers such as polyvinylpyrrolidone, carboxymethylcellulose, bovine serum albumin, and hyaluronan. The first measurement was a fluorescence intensity of the anionic form of 3-hydroxy naphtholic acid which undergoes an intramolecular proton transfer in the excited state then the steady-state fluorescence anisotropy of 3-hydroxy naphtholic acid and also the lifetime of the fluorescent probe. The measured data were evaluated in terms of interaction of the fluorescence probe with hydration shell of polymer in an aqueous environment by determination of a binding constant of the system, polymer - fluorescent probe. The interaction between anionic form of the probe with polymer was found in BSA, PVP and CMC systems. There was no interaction of fluorescent probe with hydration shell of hylauronan due to charge repulsion between the probe and hyaluronan.
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