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Wyszukujesz frazę "Liquid Chromatography" wg kryterium: Wszystkie pola


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:
Enzymatic oxidation of neobetanin monitored by liquid chromatography with mass spectrometric detection
Autorzy:
Starzak, K.
Szot, D.
Skopińska, A.
Swiergosz, T.
Wybraniec, S.
Powiązania:
https://bibliotekanauki.pl/articles/115945.pdf
Data publikacji:
2016
Wydawca:
Fundacja na Rzecz Młodych Naukowców
Tematy:
neobetanin
betalains
betacyanins
horseradish peroxidase
oxidation
enzymatic
spectrophotometry
mass spectrometry
chromatography
neobetanina
betalainy
betacyjaniny
peroksydaza chrzanowa
enzymatyczne utlenianie
spektrofotometria
spektrometria masowa
chromatografia
Opis:
The aim of this study was monitoring of enzymatic oxidation of neobetanin, an interesting type of betalains which is a partially oxidized betacyanin. As it belongs to betalains, it is water soluble and non-toxic, but a presence of a few functional groups makes it very reactive. Oxidation reactions were performed using horseradish peroxidase followed by spectrophotometric and mass spectrometric detection (LC-DAD-ESI-MS/MS) of obtained products. Enzymatic oxidation of neobetanin leads to a formation of new decarboxy- and dehydro-derivatives. The main identified oxidation product is 2-decarboxy-2,3-dehydroneobetanin. Searching for all formed oxidation products is extremely important for elucidation of the betalains oxidation mechanism.
Źródło:
Challenges of Modern Technology; 2016, 7, 1; 29-31
2082-2863
2353-4419
Pojawia się w:
Challenges of Modern Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phenobarbital analysis in biological matrix (blood) by high performance liquid chromatography (HPLC)
Autorzy:
Hamza, O.
Mohamed Moktar, B.
Chohra Mostafa, B.
Zeghdaoui, A.
Powiązania:
https://bibliotekanauki.pl/articles/412593.pdf
Data publikacji:
2014
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Phenobarbital
HPLC
blood
extraction
biological matrix
Opis:
In this work, we have tried to contribute to the analysis of phenobarbital in the blood. To do this, we used different analytical techniques such as liquid chromatography (HPLC). The results obtained in the course of our work, we can conclude that: The HPLC method was separate phenobarbital endogenous blood components, and optimizing the conditions of chromatographic separation as the composition of the mobile phase consisting of 20 % acetonitrile + 20 % methanol + 60 % ammonium acetate buffer. The extraction with diethyl ether to pH = 4; The chromatographic column, microbondapack ZORBAX C18. A system of diode-array UV detection at 254 nm.
Źródło:
International Letters of Chemistry, Physics and Astronomy; 2014, 1; 31-40
2299-3843
Pojawia się w:
International Letters of Chemistry, Physics and Astronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High-performance liquid chromatography in the analysis of drugs released from polymeric coatings
Autorzy:
Płonka, Joanna
Simka, Wojciech
Kazek-Kęsik, Alicja
Powiązania:
https://bibliotekanauki.pl/articles/283994.pdf
Data publikacji:
2019
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Polskie Towarzystwo Biominerałów
Źródło:
Engineering of Biomaterials; 2019, 22, no.153; 14
1429-7248
Pojawia się w:
Engineering of Biomaterials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sample Preparation for Determination of Biological Thiols by Liquid Chromatography and Electromigration Techniques
Autorzy:
Bald, Edward
Powiązania:
https://bibliotekanauki.pl/articles/896289.pdf
Data publikacji:
2004
Wydawca:
Uniwersytet Łódzki. Wydawnictwo Uniwersytetu Łódzkiego
Tematy:
sample preparation
liquid chromatografy
capillary electrophoresis
chemical derivatization
biological thiols
Opis:
Wydrukowano z dostarczonych Wydawnictwu UŁ gotowych materiałów
Majority of the bioanalytical or environmental methods do not use just one chromatografie or electrophoretic step, but rather involve several sample pretreatment steps which simplfy the matrix, and often preconcentrate and chemically modify the analytes. This work surveys typical procedures for sample preparation for most commonly analyzed biofluids with particular emphasis placed on chemical derivatization of sulfur amino acids for their determination by liquid phase separation techniques. Recent author's laboratory contribution to the development of sample preparation procedures is merked.
Źródło:
Acta Universitatis Lodziensis. Folia Chimica; 2004, 13
0208-6182
Pojawia się w:
Acta Universitatis Lodziensis. Folia Chimica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Derywatyzacja chemiczna w wysokosprawnej chromatografii cieczowej
The chemical derivatization in high performance liquid chromatography
Autorzy:
Kamińska, A.
Krawczyk, M. J.
Chwatko, G.
Powiązania:
https://bibliotekanauki.pl/articles/172086.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
wysokosprawna chromatografia cieczowa
derywatyzacja
grupa chromoforowa
high performance liquid chromatography
derivatization
chromophoric group
Opis:
High performance liquid chromatography (HPLC) is a method used to determine inorganic and organic substances in biological samples. Nevertheless, many analytes cannot be detected using HPLC method, because they do not contain a necessary chromophoric or fluophoric groups. Derivatization is the solution of this problem. This process can be defined as a conversion of analyte to corresponding derivative which possesses in its structure a moiety compatible with suitable detector [1, 2]. Reagent responsible for conversion of analyte to a derivative needs to meet a lot of requirements. It needs to be selective e.g. to react only with analysed substances and it should not generate by-products. The derivatization reagent should react rapidly, quantitatively, at lowest possible temperature and weakly pH, and the excess of reagent should be easily removable from reaction medium [1, 3, 5]. The derivatization can be carried out in pre-column, post-column and on-column mode. In the pre-column derivatization, analytes are derivatized before injection on HPLC system, and the reaction products are separated and detected. In the post-column derivatization, the reaction is performed automatically by adding the derivatization reagent after separation but before detection. The third method is based on reaction, which simultaneously proceeds with column separation [2, 3, 5, 6]. The derivatization processes in gas and liquid chromatography are subject matter among researcher from all over the world. The Polish literature has only few review articles on derivatization process in liquid chromatography [2, 4, 55]. The present article reviews derivatization techniques used in HPLC. Derivatization techniques used in gas chromatography are classified due to the chemical nature of derivatization reagent [3, 56]. Our attention is focused on the analyte and derivatization reagent, which can be react with various functional groups such as amino, sulfhydryl, hydroxyl or carboxyl groups, occurring in the examined molecules. By chemically modification compounds into derivatives, they obtain necessary properties for chromatographic separation and accurate analysis.
Źródło:
Wiadomości Chemiczne; 2016, 70, 11-12; 771-802
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of tylosin and tilmicosin residues in meat by high-performance liquid chromatography method
Autorzy:
Gürel Yücel, M.
Seçilmiş, H.
Taşçı, F.
Powiązania:
https://bibliotekanauki.pl/articles/16647456.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
meat
HPLC
tilmicosin
tylosin
Opis:
In this study, the presence and level of macrolide group antibiotics (tylosin and tilmicosin) were analyzed by the High-Performance Liquid Chromatography (HPLC) method in a total of 126 raw meat samples, including 42 chicken breast and 84 beef neck, available for consumption in the Burdur province (Turkey). The method demonstrated good linearity (R2 > 0.999) over the assayed concentration range (0.10-10 μg/mL). Intra-day and inter-day recoveries were used to express the accuracy of the method at three different levels of 0.5, 1, 2.5 μg/mL. Intraday recoveries and relative standard deviation values ranged from 97.270 (0.054)% to 98.643 (0.061)%, and inter-day recoveries and relative standard deviation values ranged from 97.057 (0.070)% to 98.197(0.042)% for tylosin. Intraday recoveries and relative standard deviation values ranged from 96.360 (0.065)% to 98.153 (0.046)%, and inter-day recoveries and relative standard deviation values ranged from 96.050 (0.058)% to 97.053 (0.096)% for tilmicosin. The limit of detection (LOD) value was calculated as 0.473 μg/kg for tylosin, and 0.481 μg/kg for tilmicosin; the limit of quantification (LOQ) value was calculated as 1.561 μg/kg for tylosin, and 1.587 μg/kg for tilmicosin. In general, tylosin and tilmicosin were determined in the range of 8-256 μg/kg and 30-447 μg/kg, respectively, in chicken breast meat samples; also, they were detected in the range of 36-1209 μg/kg and 30-1102 μg/kg, respectively, in beef neck meat samples. It was also found that the residues of tylosin and tilmicosin in chicken and beef meats from the market were at a much higher level than the acceptable limits specified in the regulations. This creates serious problems in terms of the ecosystem, food technology, and public health, and causes significant economic losses.
Źródło:
Polish Journal of Veterinary Sciences; 2023, 26, 1; 39-46
1505-1773
Pojawia się w:
Polish Journal of Veterinary Sciences
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
Powiązania:
https://bibliotekanauki.pl/articles/2174914.pdf
Data publikacji:
2022
Wydawca:
Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:
liquid chromatography
HPLC
phthalates
REACH
PVC
polyvinyl chloride
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.
Źródło:
Rocznik Ochrona Środowiska; 2022, 24; 190--201
1506-218X
Pojawia się w:
Rocznik Ochrona Środowiska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simultaneous determination of lopinavir, saquinavir and ritonavirin in human plasma using liquid chromatography – ion trap mass spectrometry
Autorzy:
Lipiński, Marcin
Bielawski, Krzysztof P.
Słomińska, Ewa M.
Smoleński, Ryszard T.
Powiązania:
https://bibliotekanauki.pl/articles/1891025.pdf
Data publikacji:
2021-12-02
Wydawca:
Gdański Uniwersytet Medyczny
Tematy:
antiviral therapy
lopinavir
saquinavir
ritonavir
LC/MS
Opis:
Background: Lopinavir, saquinavir, and ritonavir are viral protease inhibitors (PIs) developed for and widely used in the therapy of human immunodeficiency virus (HIV)-related disease. These compounds are also active in vitro against the pathogens causing tuberculosis, malaria and coronavirus infections. PIs have been regarded as a platform for the design of inhibitors targeting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-encoded proteases. This study aimed to develop a liquid chromatography/mass spectrometry (LC/MS) procedure for accurate simultaneous determination of concentrations of these three PIs in the plasma. Methods: Samples of human plasma were protein precipitated with 0.3 M zinc sulfate in a water/methanol solution (30:70, v/v). The extracts were analyzed with reversed-phase chromatography coupled with the electrospray ionization (ESI) source of the ion trap mass detector operating in mEass spectrometry (MS) and tandem mass spectrometry (MS/MS) modes. Results: Calibration curves demonstrated good linearity from 0.01 to 10 µg/mL and acceptable reproducibilities and recoveries. Conclusions: The described procedure proves that a very basic ion-trap LC/MS system could be applied for selective, rapid, and precise determination of antiviral protease inhibitors.
Źródło:
European Journal of Translational and Clinical Medicine; 2021, 4, 2; 60-67
2657-3148
2657-3156
Pojawia się w:
European Journal of Translational and Clinical Medicine
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Różne oblicza wodnej fazy ruchomej w chromatografii cieczowej
Miscellaneous aspects of the aqueous mobile phase in liquid chromatography
Autorzy:
Dembek, Mikołaj
Bocian, Szymon
Powiązania:
https://bibliotekanauki.pl/articles/171544.pdf
Data publikacji:
2020
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
chromatografia cieczowa
czysta woda
wodna chromatografia cieczowa
fazy stacjonarne z wbudowanymi grupami polarnymi
liquid chromatography
pure water
per aqueous liquid chromatography
polar embedded stationary phases
Opis:
Nowadays analytical chemistry, and especially chromatographic techniques, are becoming more and more popular, for example in the pharmaceutical industry [1]. Due to the increasing number of analyses, the amount of chromatographic waste is also increasing. They are harmful and toxic both to the environment and to humans. Therefore, there is a need to search for new solutions, apparatus and materials to achieve the so-called "green chromatography" [1]. Such a goal can be achieved by various methods. The most popular are miniaturization of analyses to reduce the amount of waste, reduction of analysis time, replacement of solvents with biodegradable ones, or application of aquatic conditions of analysis [2]. The following paper deals with the issue of using only water as a mobile phase for analysis in liquid chromatography. This mainly involves the use of appropriate conditions, materials and equipment. A change in the conditions of the analysis affects, first of all, the changes in the properties of water which is a mobile phase. When the temperature increases dielectric constant, viscosity and polarity of the water decreases. Optimizing these properties can allow successful separation using only water as a mobile phase [3, 4]. The following article also deals with the issue of the relatively new PALC [5] (per aqueous liquid chromatography) technique (see Fig. 3) and the analysis with the use of pure water as an eluent at room temperature, thanks to the use of polar-embedded and polar-endcapped stationary phases [6]. The latter technique is the most desirable, because it does not require the application of unusual conditions of chromatographic analysis, and at the same time fits perfectly into the assumptions of "green chromatography". The promising results of these techniques give a forward-looking view of liquid chromatography as an environmentally friendly technique.
Źródło:
Wiadomości Chemiczne; 2020, 74, 1-2; 89-106
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł

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