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Pozycja Optical properties of (3-(acetamidomethyl)phenyl) boronic acid and its interactions with selected sugars(Wydawnictwo Politechniki Łódzkiej, 2018) Kur, Katarzyna; Przybyt, Małgorzata; Miller, Ewa(3-(Acetamidomethyl)phenyl)boronic acid (3AAPBA)has at pH 7 absorbance maximum at 270 nm with molar absorbance coefficient 516 M-1cm-1. 3AAPBA exhibits weak fluorescence with maximum at 297 nm and quantum yield 0.062 ± 0.001. Fluorescence decay is monoexponential and the lifetime is 2.05 ± 0.01 ns. Interactions of 3AAPBA with selected sugars were studied by absorbance, steady-state and time-resolved fluorescence measurements. At pH 7 fluorescence of 3AAPBA is quenched only by fructose (with quenching constant 67.9 M-1) and to some extend by galactose. Addition of these two monosaccharides causes also changes of absorbance spectra of 3AAPBA. Acid-base dissociation of free 3AAPBA and its esters with sugars was studied by absorbance and steady-state fluorescence measurements in pH range from 4.5 to 11.00. Esterification of phenylboronic acid derivatives by sugars leads to increased acidity of them. In case of 3AAPBA the obtained values of pK indicate that affinity of studied sugars towards it can be ordered as follows: fructose > galactose > glucose > maltose > lactose > sucrose. At pHs higher than pK the fluorescence decays turn to biexponential with additional shorter component in lifetime which we propose to attribute to anionic form of 3AAPBA or its esters.Pozycja Polish plants as raw materials for cosmetic purposes(Wydawnictwo Politechniki Łódzkiej, 2019) Mietlińska, Katarzyna; Przybyt, Małgorzata; Kalemba, DanutaThe cosmetics market is more and more demanding, and there is a constant request for new products. The aim of the study was to find plant materials occurring commonly in Poland that would have a multidirectional effect on the skin. Research focuses on plants with high content of saponins and polyphenols. Ability to create foam and ability to reduce the surface tension of water as a determinant of saponin content was checked. The Folin-Ciocalteu test was made to check the content of polyphenols. Fifty-seven raw materials were examined. To the most promising for cosmetic purposes belong goldenrods (Solidago), especially their leaves. Much better resu lts were obtained for S. canadensis and S. gigantea, than S. virgaurea.Pozycja The study of phenylboronic acid optical properties towards creation of a glucose sensor(Wydawnictwo Politechniki Łódzkiej, 2014) Kur-Kowalska, Katarzyna; Przybyt, Małgorzata; Miller, EwaThe article presents influence of pH and glucose concentration on phenylboronic acid (PBA) fluorescence studied by steady-state and time-resolved measurements. Fluorescence of PBA decreases with growing pH. These changes reflected acid-base equilibrium of PBA and allowed to estimate value of pKd as 9.2, which is comparable with literature data. Fluorescence intensity of phenylboronic acid is quenched in presence of glucose. The effect of quenching is more pronounced with increasing pH. At pH 7 quenching can be described by Stern-Volmer equation, at pH 8 and 9 by modified one. The obtained quenching constants are growing with pH increase. The quenching of phenylboronic acid fluorescence by glucose is a static one, which is confirmed by time-resolved measurements. Two lifetimes were found for fluorescence decay of phenylboronic acid. The lifetimes are practically independent on pH and glucose concentration and also fraction of both lifetimes are nearly the same. The obtained Stern-Volmer constants can be interpreted as apparent equilibrium constants of ester formation between acid and glucose.Pozycja Lactate biosensors for food industry(Wydawnictwo Politechniki Łódzkiej, 2014) Przybyt, MałgorzataLactic acid and lactate fermentation play important role in food and beverages production, control and quality. Analysis of lactate by standard methods is time, work consuming, and cannot be implemented at the production site. The alternative is the use of biosensors for lactate. The article reviews the biosensors for D- and L-lactic assay, their types, construction and application in food analysis area. The special emphasis is given to the commercial biosensor for lactate. The market survey indicates that there is a lack of lactate biosensors addressed to food industry except wine production. QUALI_JUICE project was the practical attempt to use some of the commercial biosensors in production and quality control in fruit juice industry. The results of the project indicates that commercial biosensors can be used after some minor functional adaptation in fruit juice production control. The application of these biosensors can be broadened to the other sectors of food and beverage industry.Pozycja ZnS Cu-doped quantum dots(Wydawnictwo Politechniki Łódzkiej, 2014) Ziółczyk, Paulina; Miller, Ewa; Przybyt, MałgorzataThe paper presents a survey of literature on the structure and optical properties of ZnS and copper ion-doped ZnS quantum dots. The effect of other metal dopants on the spectral properties of ZnS:Cu quantum dots was also considered. The influence of such parameters as dopant concentration, temperature of the synthesis and compounds which form or modify the additional layer on dots on spectral properties of the quantum dots was described. Examples of application of ZnS:Cu quantum dots are also given.