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Wyszukujesz frazę "liquid chromatography" wg kryterium: Temat


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.
Tematy:
micellar liquid chromatography
retention mechanism
sulfonamides
Pokaż więcej
Wydawca:
Politechnika Bydgoska im. Jana i Jędrzeja Śniadeckich. Wydział Technologii i Inżynierii Chemicznej
Powiązania:
https://bibliotekanauki.pl/articles/347039.pdf  Link otwiera się w nowym oknie
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.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Separation of nonreacted acrylamide from polyacrylamide gel for endoprothesing
Autorzy:
Gertsyuk, M.
Samchenko, Y.
Tematy:
hydrogels
acrylamide
acrylic monomers
liquid chromatography
endoprothesis
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Wydawca:
Politechnika Bydgoska im. Jana i Jędrzeja Śniadeckich. Wydział Technologii i Inżynierii Chemicznej
Powiązania:
https://bibliotekanauki.pl/articles/346993.pdf  Link otwiera się w nowym oknie
Opis:
The separation of toxic acrylic monomers (mainly acrylamide) from some polymeric hydrogels of medical application was studied. It was found that “clean hydrogel” can be obtained after 4-6 days of washing with nonpyrogenic water. The quantity of monomeric acrylamide remained in the samples was controlled by a liquid chromatography method.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Food quality control by hyphenated separation techniques
Autorzy:
Walczak, J.
Pomastowski, P.
Buszewski, B.
Tematy:
food analysis
hyphenated techniques
liquid chromatography
mass spectrometry
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Wydawca:
Akademia Bialska Nauk Stosowanych im. Jana Pawła II w Białej Podlaskiej
Powiązania:
https://bibliotekanauki.pl/articles/2052456.pdf  Link otwiera się w nowym oknie
Opis:
Food as complex mixture of proteins, lipids, vitamins, etc. cannot be separated and identified by using in only one method. This article presents a revision on the hyphenated chromatographic techniques and methods used in food analysis and described main application in food science research, and determination of xenobiotics and their metabolites in environmental. Also article discusses applications of “omics” in food analysis (proteomics, transcriptomics, genomics, metabolomis) and new discipline of – foodomics.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Retention mechanism of sulfonamides in micellar reversed phase liquid chromatography
Autorzy:
Szymański, A.
Tematy:
micellar liquid chromatography
quantitative structure-activity relationships
sulfonamides
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Wydawca:
Politechnika Bydgoska im. Jana i Jędrzeja Śniadeckich. Wydział Technologii i Inżynierii Chemicznej
Powiązania:
https://bibliotekanauki.pl/articles/347037.pdf  Link otwiera się w nowym oknie
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.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
DETERMINATION OF ACYCLOVIR IN RABBIT PLASMA BY HIGH PERFORMANCE LIQUID CHROMATOGRAPHIC (HPLC) TECHNIQUE
Autorzy:
Malik, Nadia S.
Ahmad, Mahmood
Minhas, Muhammad U.
Khalid, Qandeel
Tematy:
plasma
acyclovir
Reversed phase high-performance liquid chromatography
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Wydawca:
Polskie Towarzystwo Farmaceutyczne
Powiązania:
https://bibliotekanauki.pl/articles/895236.pdf  Link otwiera się w nowym oknie
Opis:
A rapid, sensitive and simple reversed-phase high-performance liquid chromatographic (HPLC) method has been developed and validated for the determination of acyclovir (ACV) in rabbit plasma. BDS C18 column was used to conduct analysis using ammonium dihydrogen phosphate buffer (50mM) and methanol as mobile phase (98:2), with pH adjusted to 2.5 using orthophosphoric acid. Flow rate was kept at 1 mL/min. Selective precipitation of plasma proteins were done by adding 5% perchloric acid. Precipitated plasma proteins were separated by centrifugation. ACV moves in a supernatant, which was snapped and passed through a syringe filtration assembly. Direct injection of supernatant was given into a BDS C18 column and ACV was detected at 256 nm. The limit of detection for ACV in plasma was estimated as 15ng/mL whereas the limit of quantitation was calculated as 25 ng/mL. Moreover, the developed method has been found to be selective and linear into concentration range of 25 – 2000 ng/mL. The present method could be successfully applied to samples from bioavailability and bioequivalence studies.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Sensitive Method of Determination of Hazardous Phthlates in Polymeric Building Materials by High Performance Liquid Chromatography
Autorzy:
Kaniowska, Elżbieta
Kaczmarczyk, Grzegorz
Tematy:
liquid chromatography
HPLC
phthalates
REACH
PVC
polyvinyl chloride
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Wydawca:
Politechnika Koszalińska. Wydawnictwo Uczelniane
Powiązania:
https://bibliotekanauki.pl/articles/2174914.pdf  Link otwiera się w nowym oknie
Opis:
Polymeric building materials and equipment for indoor use in spaces intended for people may, in an essential way, contribute to the deterioration of wholesome quality of life. Phthalates, present in many products, constitute an omnipresent group of compounds used widely as plasticisers. The research results show that these substances may negatively impact human health, and thus European Union has implemented several regulatory measures restricting their use. Manufacturers and suppliers must comply with these regulations. As a result, it is necessary to investigate and determine the contents of phthalates in these materials. This paper presents the analytic profile of the method of marking phthalates extracted from polyvinyl chloride using HPLC chromatography with UV-VIS detection and selected results obtained in examinations of materials used in interior design. The results of described examinations of phthalates content indicate that not all materials recommended by manufacturers may be used indoors in spaces intended for people. The method was verified for its suitability for routine analyses of materials made of PVC and submitted for attestation. The elaborated method can be used to determine the banned phthalates’ presence in PVC. The method allows for detecting these phthalates at the level required by the REACH regulation, and its validation parameters are highly satisfactory considering a very complex matrix.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Chromatographic methods for determination of neopterin in urine
Chromatograficzne metody oznaczania neopteryny w moczu
Autorzy:
Waligóra, A.
Waligóra, S.
Tyrpień-Golder, K.
Tematy:
neopteryna
pterydyny
chromatografia cieczowa
ELISA
neopterin
pteridines
liquid chromatography
Pokaż więcej
Wydawca:
Centralny Ośrodek Badawczo-Rozwojowy Aparatury Badawczej i Dydaktycznej, COBRABiD
Powiązania:
https://bibliotekanauki.pl/articles/270489.pdf  Link otwiera się w nowym oknie
Opis:
Neopterin is considered to be a non-specific marker for the activation of the human immune system. It is synthesized by monocytes/macrophages in the immune response caused by T cells. The physiological role of neopterin and its derivatives is based on the modulation of macrophage cytotoxicity by enhancing the activity of reactive oxygen species under certain conditions. The concentration of neopterin is regarded as the evaluation parameter of oxidative stress immunologically induced. High concentrations of neopterin were observed in biological fluids of patients with bacterial infection, viral, autoimmune diseases and cancer and vascular diseases. At the proper neopterin elimination from the body, its concentrations in urine correlate to those in the serum or plasma. Measuring the concentration of neopterin is important in monitoring of the course of immunological activity in disease. In special cases, the determination of neopterin concentration was used in the differential diagnosis. This paper describes various methods for determining neopterin in urine primarily by high performance liquid chromatography (HPLC), and enzyme-linked immunosorbent assay (ELISA). HPLC techniques are predominant due to the possibility of modifying the chromatographic system and other parameters. The combination of these methods may be useful in developing new analytical procedures for determining neopterin in urine.
Neopteryna, uważana za niespecyficzny marker aktywacji ludzkiego układu odpornościowego, syntezowana jest przez monocyty/makrofagi w odpowiedzi immunologicznej wywołanej przez limfocyty T. Fizjologiczna rola neopteryny oraz jej pochodnych polega na modulowaniu cytotoksyczności makrofagów poprzez zwiększanie aktywności reaktywnych form tlenu w określonych warunkach. Stężenie neopteryny jest uznawane za parametr oceny stresu oksydacyjnego wywołanego stanem zapalnym, a jej wysokie stężenia odnotowano m.in. w płynach biologicznych osób z infekcją bakteryjną, wirusową, chorobami autoimmunologicznymi i nowotworowymi oraz z chorobami układu krwionośnego. Przy prawidłowej eliminacji neopteryny z organizmu jej stężenie w moczu jest skorelowane z oznaczanymi w surowicy lub w osoczu. Oznaczanie stężenia neopteryny ma istotne znaczenie w monitorowaniu ak tywności immunologicznej wielu chorób. W szczególnych przypadkach oszacowanie jej stężenia w materiale biologicznym znalazło zastosowanie w diagnostyce różnicowej. W pracy zostały opisane różne metody oznaczania neopteryny w moczu, głównie z zastosowaniem wysokosprawnej chromatografii cieczowej (HPLC) i kompetycyjnego testu immunoenzymatycznego (ELISA). Dominują głównie techniki chromatograficzne (HPLC), ze względu na możliwość modyfikacji układu chromatograficznego oraz innych parametrów. Zestawienie tych metod może być pomocne w opracowaniu nowych procedur analitycznych oznaczania neopteryny w moczu.
Dostawca treści:
Biblioteka Nauki
Artykuł

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