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Wyszukujesz frazę "Szymanski, A." wg kryterium: Autor


Wyświetlanie 1-5 z 5
Tytuł:
Retention mechanism of sulfonamides in micellar reversed phase liquid chromatography
Autorzy:
Szymański, A.
Powiązania:
https://bibliotekanauki.pl/articles/347037.pdf
Data publikacji:
2011
Wydawca:
Politechnika Bydgoska im. Jana i Jędrzeja Śniadeckich. Wydział Technologii i Inżynierii Chemicznej
Tematy:
micellar liquid chromatography
quantitative structure-activity relationships
sulfonamides
Opis:
A mechanism of retention of sulfonamides in the micellar liquid chromatography, based on similar models verified for other compounds, was proposed. The magnitudes of hydrophobic and electrostatic interactions of sulfonamides were estimated for different concentrations of surfactant in the mobile phase and at varied pH. With increasing SDS concentrations and at a constant pH, a decrease in the hydrophobic interaction intensity was noted. When pH is varied, the values of the constant, describing the hydrophobicity of the sulfonamides, remained at an approximately same level (taking into account the standard deviation values). Greater differences were observed in the constants related to the electrostatic interactions informing about the increase or decrease in retention, following from ionic interactions. For each sulfonamide, the molar fraction of the ionic fractions present in the mobile phase was calculated from the formula derived, which permitted determination of the type of electrostatic interactions, varying with the eluent’s changing pH. On the basis of the chromatographic data collected, it was established that retention of sulfonamides in the SDS micellar system depends on the hydrophobic and electrostatic interactions. For varied pH values, the hydrophobic interactions of sulfonamides did not change significantly, all changes in the retention of the sulfonamides were attributed to changes in the electrostatic interactions.
Źródło:
Ars Separatoria Acta; 2011, 8; 69-80
1731-6340
Pojawia się w:
Ars Separatoria Acta
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Relationship between micellar liquid chromatography retention of sulfonamides and the pH and concentration of surfactants and organic modifiers in the mobile phase
Autorzy:
Szymański, A.
Powiązania:
https://bibliotekanauki.pl/articles/347039.pdf
Data publikacji:
2011
Wydawca:
Politechnika Bydgoska im. Jana i Jędrzeja Śniadeckich. Wydział Technologii i Inżynierii Chemicznej
Tematy:
micellar liquid chromatography
retention mechanism
sulfonamides
Opis:
The paper presents an attempt to adapt a retention model suggested and verified by classic RP LC in micellar liquid chromatography, MLC. Instead of hydrophobic interactions with ODS groups and electrostatic interactions with silanol residues in C-18 packing, hydrophobic interactions with alkyl groups and ionic interactions with anionic moieties of the SDS-modified stationary phase were considered. Due to the different characteristics of the stationary phase in the MLC depending on the pH of the mobile phase, the equation used to determine the contribution of electrostatic interactions to retention was modified. Theoretical curves for the relationship between retention and SDS micelle concentration in the mobile phase, organic modifier concentration and eluent pH were determined. For comparison, curves based on data obtained in basic sulfonamide studies were plotted in the same coordinate systems and units. A complete qualitative similarity was noted between the theoretical curves predicting retention changes with changing micellar mobile phase parameters and the curves determined based on experimental results for the sulfonamides. The qualitative similarity involves a similar shape of the respective curves and identical tendencies. In general, a larger reduction of sulfonamide retention with respect to the predicted value is noted. The deviation results from changes in the sulfonamide property with changing pH of the mobile phase.
Źródło:
Ars Separatoria Acta; 2011, 8; 51-67
1731-6340
Pojawia się w:
Ars Separatoria Acta
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effect of the concentration of the ionic liquid didecyldimethylammonium lactate on the retention and separation of pyrimidine bases
Autorzy:
Szymański, M.
Zapart, J.
Florek, G.
Szymański, A.
Powiązania:
https://bibliotekanauki.pl/articles/347003.pdf
Data publikacji:
2013
Wydawca:
Politechnika Bydgoska im. Jana i Jędrzeja Śniadeckich. Wydział Technologii i Inżynierii Chemicznej
Tematy:
ionic liquids
reversed-phase high-performance liquid chromatography
additives
Opis:
Ionic liquids (IL) are new materials with a wide spectrum of use. Being a variable combination of an organic cation and an organic or inorganic anion, their have controllable properties. The effect of the ionic liquid added to the mobile phase on the separation of uracil derivatives is studied and demonstrated in this paper. The ionic liquid used was didecyldimethylammonium lactate, which has an advantageous effect on the separation of the analytes studied. Pyrimidine bases which were used as the test compounds are characterized by alkaline properties due to which so-called peak tailing is observed during separation. A methanol/water mixture was used as the mobile phase in the chromatographic analyses. Optimum separations were obtained for 8% levels of the organic modifier. The best separations of the test isomers were obtained for 0.01% IL added to the mobile phase. The findings obtained are evidence that the use of ionic liquids in HPLC is an efficient method for the separation of polar compounds: the duration of the analysis is shorter and the resulting peaks are sharp and symmetrical.
Źródło:
Ars Separatoria Acta; 2012-2013, 9/10; 15-24
1731-6340
Pojawia się w:
Ars Separatoria Acta
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Determination of trace quantities of dutasteride in water and wastewater by solid phase extraction and high-performance liquid chromatography
Autorzy:
Wasilewska, A.
Madajczyk, M.
Szymański, A.
Urbaniak, W.
Powiązania:
https://bibliotekanauki.pl/articles/347041.pdf
Data publikacji:
2011
Wydawca:
Politechnika Bydgoska im. Jana i Jędrzeja Śniadeckich. Wydział Technologii i Inżynierii Chemicznej
Tematy:
dutasteride
emerging pollutants
solid-phase extraction (SPE)
liquid chromatography
HPLC
Opis:
Steroid compounds are a kind of pollutants which are increasingly more frequently found in environmental samples. Due to the ever more increasing level of such pollutants and their biological activity, they are of interest to analysts. Our study involved the development of a simple and fast method for the assay of dutasteride in treated industrial waste water using high-performance liquid chromatography. As the steroid concentration in water is much lower than the limit of detection of the UV detector used, the compound assayed in the test water was pre-concentrated using solid-phase extraction. Our procedure has high accuracy and a precision of 2.6%, and the recovery of the analyte from water is 78.6%. The procedure enables the assay of dutasteride at a level of 2 microg/L in water.
Źródło:
Ars Separatoria Acta; 2011, 8; 39-49
1731-6340
Pojawia się w:
Ars Separatoria Acta
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Determination of oleuropein in herbal preparation and Olea europaea L. extracts by HPLC
Autorzy:
Szymański, M.
Witkowska-Banaszczak, E.
Matławska, I.
Szymański, A.
Powiązania:
https://bibliotekanauki.pl/articles/346909.pdf
Data publikacji:
2013
Wydawca:
Politechnika Bydgoska im. Jana i Jędrzeja Śniadeckich. Wydział Technologii i Inżynierii Chemicznej
Tematy:
oleuropein
Olea europaea L.
herbal products
high performance liquid chromatography
Opis:
Oleuropein is a secoiridoide monoterpene. It is found primarily in all parts of the Olea europaea L. tree, mostly in its unripe fruit and leaves. It has a number of beneficial effects on the human body, being readily absorbed from the gastrointestinal tract due to its hydrophilic properties. The paper presents a simple, rapid and precise method for the assay of oleuropein in herbal formulations and the European Olive leaf extract. Chromatographic separation was performed using a C-18 column with an acetonitrile/water 20/80% vol. mixture as the mobile phase. The method has a wide range of linearity between 0.05 and 1.5 mg/mL, very good repeatability of retention time, and accuracies between 95.8 and 103.3%. Its limit of detection is 0.04 mg/mL. The developed method was tested on two herbal formulations which are commercially available in Poland.
Źródło:
Ars Separatoria Acta; 2012-2013, 9/10; 55-63
1731-6340
Pojawia się w:
Ars Separatoria Acta
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-5 z 5

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