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    Wyświetlanie 1-12 z 12
    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:
    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
    Tytuł:
    Izoflawony – struktura, aktywność biologiczna oraz metody oznaczania przy użyciu wysokosprawnej chromatografii cieczowej
    Isofalvones – structure, biological activity and determination by high performance liquid chromatography
    Autorzy:
    Bachanek, I.
    Czauderna, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/171515.pdf
    Data publikacji:
    2014
    Wydawca:
    Polskie Towarzystwo Chemiczne
    Tematy:
    izoflawony
    przygotowanie próbek
    oznaczanie związków izoflawonowych
    wysokosprawna chromatografia cieczowa
    HPLC
    isoflavone
    sample preparation
    determination
    high performance liquid chromatography
    Opis:
    Isoflavones are a subclass of flavonoids and are also described as phytoestrogen compounds, since they exhibit estrogenic activity (similar effects to estradiol hormones). The basic characteristics of isoflavone structure is a flavone nucleus, composed of two benzene rings (A and B) linked to a heterocyclic ring C (Fig. 1). The benzene ring B position is the basis for the categorization of a flavanoid class (position 2) and a isoflavonoid class (position 3) [8]. Isoflavones are classified according to substitutions. The glucoside forms can be esterified at the 6’’-O-position of the glucose ring with malonyl or acetyl groups forming another compounds. In food and plants, flavonoids exist primarily as 3-O-glycosides and polymers [14]. Isoflavonoids are a group of chemical compounds which is widely distributed in the vegetable world. Their biological activity has found remarkable pharmaceutical, therapeutic, dietary and nutritional applications. The structure of phytoestrogens enables them to bind to the estrogen receptors (ERs), they are similar to 17β-estradiol, contain an aromatic ring with hydroxyl group and have the binding affinity to both estrogen. In addition, isoflavones interact with the metabolism of steroid hormones. Recently, they have come into focus of interest due to several reports about their positive effect on human health, in particular prevention of hormone-dependent cancers, cardiovascular diseases, osteoporosis, adverse menopausal manifestations and age-related cognitive decline. To identify the potential health benefits associated with the consumption of isoflavones, it is of critical importance to have high-quality and comprehensive data. To this end, adequate analytical methodologies are essential for a reliable and exact identification as well as for quantification. Moreover, methodologies and techniques used need to keep up with technology to improve the performance in terms of resolution, efficiency, precision, reproducibility and speed, allowing a proportionate increase in the amount and quality of information gathered [7]. Common methods for the extraction of isoflavones from soybeans and soy products include organic solvent extraction with aqueous methanol, ethanol or acetonitrile, using simple mixing, ultra-sonification or refluxing techniques [24]. The application of micro-scale and nano-scale extraction and separation techniques is the most likely future development, resulting in quick, sensitive analytical methods for sample preparation and analysis of flavonoids and their metabolites. Miniaturization, high-throughput systems utilizing new sorbents and automation of chromatographic systems are of great interest in clinical, pharmaceutical, environmental and food fields. The most used analysis technique for the quantification of isoflavones in solid samples is, with no doubt, reversed-phase HPLC using C18 based columns with water and methanol or acetonitrile containing small amounts of acid as a mobile phase [7].
    Źródło:
    Wiadomości Chemiczne; 2014, 68, 7-8; 661-681
    0043-5104
    2300-0295
    Pojawia się w:
    Wiadomości Chemiczne
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Fazy stacjonarne do chromatografii cieczowej z wbudowanymi grupami polarnymi : synteza i właściwości powierzchniowe
    Chemically bonded stationary phases with incorporated polar groups for liquid chromatography : the synthesis and surface properties
    Autorzy:
    Bocian, S.
    Krzemińska, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/171968.pdf
    Data publikacji:
    2018
    Wydawca:
    Polskie Towarzystwo Chemiczne
    Tematy:
    chromatografia cieczowa
    fazy stacjonarne
    wbudowane grupy polarne
    właściwości powierzchniowe
    procesy solwatacyjne
    liquid chromatography
    stationary phases
    polar embedded stationary phases
    surface properties
    solvation processes
    Opis:
    In recent years high performance liquid chromatography (HPLC) has gained a dominant position in the life sciences. The widespread use of this technique allows to perform an analysis of compounds which are used in various areas of human life. Currently, there are wide and fully untapped opportunities for synthesis of chromatographic packings with chemically bonded stationary phases. Some of the liquid chromatographic analyses needs the application of water-rich mobile phases (more than 85% water or a buffer). In such condition the performance of hydrophobic stationary phases indicate that the bonded ligands might be collapsing. This problem could be solved by increasing of organic content in the mobile phase which should improve solvation and bring bonded ligands back to the original conformation. To avoid this procedure, which reduces the retention and selectivity of the separation, it is possible to apply stationary phases with incorporated polar groups mixed with the original alkyl ligands (polar embedded stationary phases). Another possibility is to add some polar groups during endcapping procedure (polar end-capped stationary phases). This produces variation in the bonding. Chemically bonded stationary phases which include both hydrophobic and hydrophilic ligands are so-called mixed mode stationary pahses. These materials can be used in reversed phase liquid chromatography (RPLC) and there is also a possibility to use them in hydrophilic interaction liquid chromatography (HILIC). They allow to separate polar and non-polar analytes. Following the idea of green chemistry, especially green analytical chemistry, a series of stationary phases was synthesized. The obtained materials connect polar and hydrophobic groups in the structure of bonded ligands. These specific surface properties provide the stability of the stationary phase in pure water as a mobile phase. Surface properties of novel material were analyzed using various instrumental and chromatographic methods. Finaly, the mixtures of various compounds were applied to test the separation selectivity of stationary phases in various chromatographic system, including purely aqueous conditions.
    Źródło:
    Wiadomości Chemiczne; 2018, 72, 9-10; 685-701
    0043-5104
    2300-0295
    Pojawia się w:
    Wiadomości Chemiczne
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Chromatograficzna analiza związków budujących kwasy nukleinowe
    Chromatographic analysis of nucleic acids constituents
    Autorzy:
    Studzińska, S.
    Rola, R.
    Łobodziński, F.
    Krzemińska, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/172180.pdf
    Data publikacji:
    2016
    Wydawca:
    Polskie Towarzystwo Chemiczne
    Tematy:
    nukleozydy
    nukleotydy
    oligonukleotydy
    chromatografia cieczowa
    czułość
    selektywność
    nucleosides
    nucleotides
    oligonucleotides
    liquid chromatography
    sensitivity
    selectivity
    Opis:
    Understanding the characteristics, role and structure of nucleic acids allowed to answer questions about the disease processes. Today, nucleic acids and their constituents are tools, which are used by molecular biology in medicine and biotechnology. Antisense and gene therapy are intensively developing methods for possible treating or preventing disease. They use short fragments of DNA or RNA - oligonucleotides to silence the genes expression. They are not the only ones that allow analytical chemists to obtain information about the state of our body. Determination of modified nucleoside allows detection of cancer, while analysis of nucleotides allows the estimation of strengthening the immune system. There is a great need of sensitive, selective and precise methods of separation of nucleosides, nucleotides and oligonucleotides and their qualitative and quantitative analysis. Consequently liquid chromatography (LC) is the most commonly used for analysis of nucleic acid constituents. The most widely used modes of LC include Ion Exchange Chromatography (IEC) and Reversed Phase High Performance Liquid Chromatography (RP HPLC). Both techniques have their advantages and disadvantages in the analysis of nucleosides, nucleotides and oligonucleotides. In the case of IEC it is necessary to use high concentrations of the salt in the mobile phase or concentration gradients, which considerably limits the possibility of using MS detection. RP HPLC can be coupled with MS detection but only when volatile salts are mobile phase components. On the other hand there is a significant problem is the lack of sufficient selectivity for the most polar nucleosides and nucleotides. RP HPLC MS is still most often used in the determination of nucleosides and nucleotides, due to its high sensitivity and a comprehensive qualitative analysis. Another system used for the HPLC analysis of oligonucleotides is Ion Pair Reversed Phase High Performance Liquid Chromatography (IP RP HPLC). These compounds can not be analyzed by RP HPLC due to their high polarity. The advantage of IP RP HPLC is selectivity, achieved by a suitable choice of mobile phase composition and the possibility of using MS. A disadvantage of IP RP HPLC in the analysis of oligonucleotides is however lower sensitivity compared to RP HPLC. During the last few years Hydrophilic Interaction Liquid Chromatography (HILIC) was applied for the separation of mixtures of nucleosides, nucleotides, oligonucleotides extracted from a biological or food samples. The presented results demonstrate the usefulness of this method, however, the resolving power is limited due to the asymmetric peak shape. On the other hand proper selection of the mobile and stationary phase can lead to a high selectivity in the analysis of the most polar nucleosides, nucleotides and oligonucleotides, which can not be separated by RP HPLC.
    Źródło:
    Wiadomości Chemiczne; 2016, 70, 9-10; 633-656
    0043-5104
    2300-0295
    Pojawia się w:
    Wiadomości Chemiczne
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Wpływ modyfikatora fazy ruchomej na selektywność rozdzielenia w odwróconym układzie faz wysokosprawnej chromatografii cieczowej
    Influence of mobile phase modifier on separation selectivity in reversed phase high performance liquid chromatography
    Autorzy:
    Misiołek, B.
    Klimek-Turek, A.
    Dzido, T. H.
    Powiązania:
    https://bibliotekanauki.pl/articles/172139.pdf
    Data publikacji:
    2013
    Wydawca:
    Polskie Towarzystwo Chemiczne
    Tematy:
    retencja substancji
    selektywność rozdzielenia
    wpływ modyfikatora na selektywność
    wysokosprawna chromatografia cieczowa z odwróconym układem faz
    HPLC
    RP-HPLC
    retention of solutes
    separation selectivity
    effect of modifier on selectivity
    reversed-phase high-performance liquid chromatography
    RP HPLC
    Opis:
    High performance liquid chromatography (HPLC) is an instrumental analytical technique, which is widely used for a separation and determination of a mixture of components in many samples (e.g. of biomedical, pharmaceutical, food, and environmental origin). Despite several decades of the development of this technique, some aspects of the chromatographic process are still open to questions. This is particularly related to mechanisms of retention and selectivity of a separation. Improvement of the separation selectivity can be achieved by a change of the stationary phase type and qualitative and/or quantitative composition of the mobile phase. The replacement of the stationary phase does not ensure a smooth change of selectivity and retention, however, it generates additional costs of analysis. Therefore, the optimal conditions of chromatographic separation can be easily obtained by the change of a composition of the mobile phase, i.e. the type and/or concentration of its modifier (organic solvent). This paper presents an overview of approaches to explanation and interpretation of an influence of mobile phase composition on the retention and separation selectivity in liquid chromatography systems with particular emphasis on modifier type of eluent in the reversed phase high performance liquid chromatography (RP HPLC).
    Źródło:
    Wiadomości Chemiczne; 2013, 67, 1-2; 133-159
    0043-5104
    2300-0295
    Pojawia się w:
    Wiadomości Chemiczne
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Nowe kierunki badań i wyzwania w analizie leków heparynowych
    New directions of research and challenges in the analysis of heparin drugs
    Autorzy:
    Sadowski, Radosław
    Krysztofiak, Dominika
    Gadzała-Kopciuch, Renata
    Buszewski, Bogusław
    Powiązania:
    https://bibliotekanauki.pl/articles/1413253.pdf
    Data publikacji:
    2021
    Wydawca:
    Polskie Towarzystwo Chemiczne
    Tematy:
    technika rozdzielania
    chromatografia cieczowa
    leki przeciwzakrzepowe
    heparyny
    LMWHs
    separation technique
    liquid chromatography
    anticoagulants
    heparin
    Opis:
    The complexity of the structure of heparin anticoagulants requires appropriate sample preparation to be able to perform the analysis correctly. This stage of the analytical procedure is the most time-consuming and has a key impact on the obtained information. Therefore, it is important to improve the current and search for new solutions for the preparation of samples of anticoagulants as well as the separation and identification of components of such drugs. This paper discusses heparin drugs and new research directions and challenges related to the analytics of heparin anticoagulants.
    Źródło:
    Wiadomości Chemiczne; 2021, 75, 7-8; 935-942
    0043-5104
    2300-0295
    Pojawia się w:
    Wiadomości Chemiczne
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Dwuwymiarowa separacja technikami chromatografii i elektroforezy ze szczególnym uwzględnieniem połączenia ich w proces jednoetapowy
    Two-dimensional separation with chromatography and electrophoresis techniques with special focus on their combination into single process
    Autorzy:
    Łopaciuk, E.
    Dzido, T. H.
    Powiązania:
    https://bibliotekanauki.pl/articles/171869.pdf
    Data publikacji:
    2013
    Wydawca:
    Polskie Towarzystwo Chemiczne
    Tematy:
    separacja dwuwymiarowa
    elektroforeza
    elektrochromatografia
    chromatografia cieczowa
    rozdzielanie dwuwymiarowe ciągłe
    two dimensional separation
    electrophoresis
    electrochromatography
    liquid chromatography
    continuous two-dimensional separation
    Opis:
    Liquid chromatography and electrophoresis techniques are very often applied in contemporary laboratory practice. These techniques usually show different separation selectivity. It is due to various separation mechanisms involved in these two modes. In the former, partition of solutes between stationary and mobile phases influences on separation selectivity and retention contrary to the latter in which electrophoretic effect is involved in separation mechanism. The features mentioned are very useful for combination of these two techniques into two-dimensional separation of complicated samples of biomedical and environmental origin. Development of such approach is a very promising for contemporary separation sciences. The paper presents an overview of two-dimensional separation techniques, in which both liquid chromatography and electrophoresis have been involved especially in continuous mode.
    Źródło:
    Wiadomości Chemiczne; 2013, 67, 9-10; 899-927
    0043-5104
    2300-0295
    Pojawia się w:
    Wiadomości Chemiczne
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Zastosowanie cieczy jonowych jako modyfikatorów fazy ruchomej w chromatografii cieczowej
    Application of ionic liquids as mobile phase modifiers in liquid chromatorgaphy
    Autorzy:
    Kilanowska, Anna
    Zielak, Judyta
    Studzińska, Sylwia
    Powiązania:
    https://bibliotekanauki.pl/articles/172012.pdf
    Data publikacji:
    2020
    Wydawca:
    Polskie Towarzystwo Chemiczne
    Tematy:
    ciecze jonowe
    chromatografia cieczowa
    blokowanie wolnych silanoli
    chromatografia par jonowych
    oligonukleotydy antysensowne
    ionic liquids
    liquid chromatography
    free silanol suppressors
    ion pair chromatography
    antisense oligonucleotides
    Opis:
    Ionic liquids are molten salts composed of large, asymmetric, organic cations (e.g. imidazolium or piperidine) and inorganic anions such as e.g chloride or fluoroborate. These compounds are characterized by low melting point, below 1000C, however, they also have other interesting properties including high thermal stability, minor vapor pressure or negligible volatility. Moreover, by the appropriate selection of the cation and anion building the ionic liquid, it is possible to obtain the desired physicochemical properties of these salts. For this reason, ionic liquids are applied to the synthesis, catalysis, electrochemical methods, extraction methods, etc. Application of these compounds in separation techniques merits special attention, especially considering liquid chromatography. Ionic liquids are commonly used in this technique as free silanols suppressors, especially regarding the analysis of basic compounds. Moreover, the excess amount of ionic liquids ions may adsorb on the hydrophobic ligands present at the stationary phase surface, which also plays a significant role in the retention of analytes. Besides their application as silanols suppressors, these compounds were also used as ion pair reagents in the analysis of antisense oligonucleotides, which are short nucleic acid fragments with therapeutic potential due to the ability to bind with complementary sequences of ribonucleic acid. For this reason, antisense oligonucleotides are used in the treatment of several diseases. This article briefly presents structures, properties and the application of ionic liquids as mobile phase modifiers for the analysis of the wide range of different analytes using liquid chromatography. Moreover, a part of this paper was devoted to the analysis of antisense oligonucleotides with the use of the different chromatographic techniques, including the application of ionic liquids as mobile phase additives in ion pair chromatography.
    Źródło:
    Wiadomości Chemiczne; 2020, 74, 7-8; 507-525
    0043-5104
    2300-0295
    Pojawia się w:
    Wiadomości Chemiczne
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Metody oznaczania barwników spożywczych
    Methods for the determination of food dyes
    Autorzy:
    Kałwa, K.
    Mazurek, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/171756.pdf
    Data publikacji:
    2018
    Wydawca:
    Polskie Towarzystwo Chemiczne
    Tematy:
    barwniki spożywcze
    wysokosprawna chromatografia cieczowa
    HPLC
    spektrofotometria
    chromatografia cienkowarstwowa
    TLC
    elektroforeza kapilarna
    food dyes
    high-performance liquid chromatography
    spectrophotometry
    thin layer chromatography
    capillary electrophoresis
    Opis:
    Food dyes are chemical substances that were developed to enhance the appearance of food by giving it artificial color. People have added colorings to food for centuries, but the first artificial food colorings were created in 1856 from coal tar. Over the years, hundreds of artificial food dyes have been developed, but a majority of them have since been found to be toxic. There is only a handful of artificial dyes that are still used in food. Food manufacturers often prefer artificial food dyes over natural food colorings, such as beta carotene and beet extract, because they produce a more vibrant color [1]. However, there is quite a bit of controversy regarding the safety of artificial food dyes. All of the artificial dyes that are currently used in food have gone through testing for toxicity in animal studies. Regulatory agencies, like the US Food and Drug Administration (FDA) and the European Food Safety Authority (EFSA), have concluded that the dyes do not pose significant health risks. Not everyone agrees with that conclusion. Interestingly, some food dyes are deemed safe in one country, but banned from human consumption in another, making it extremely confusing to assess their safety [2]. Undesirable effects of azo dyes used for coloring food products led to the development of very sensitive and selective analytical methods successfully used for their determination in various food matrices. Many different methods have been employed for the determination of synthetic dyes in food and beverages including thin layer chromatography and capillary electrophoresis [3]. However, these methods can be time consuming and may not be applicable for the simultaneous analysis of many dyes. Conventional HPLC methods have been employed for the analysis of synthetic colorants and while useful, these methods require long analysis times and large amounts of expensive solvents [4, 5]. Preparation of the test sample involves the use of various techniques such as membrane filtration due to the complexity of food products. Therefore, the development of simple, selective extraction methods together with the combination of chromatographic and spectrophotometric techniques are of great importance [6]. One of the most difficult stages of the analysis is the appropriate selection of the method for the determination of food colors. In the case of spectrophotometric methods, the main advantage is the low cost of the determination, however, the lack of specificity of the absorption spectrum usually makes it difficult to apply this method in the case of a mixture of different absorbing dyes due to the overlap of the spectra. The CE (Capillary Electrophoresis) analysis is faster and more economical compared to conventional electrophoresis and chromatography. The production of cheap capillaries and the development of on-line detection systems contributed to the development of modern capillary electrophoresis. Capillary electrophoresis has a number of types of separation. Ultimately, it is impossible to determine the one particular appropriate specific method for the determination of food dyes due to their diverse structure and chemical composition [4, 7].
    Źródło:
    Wiadomości Chemiczne; 2018, 72, 9-10; 667-683
    0043-5104
    2300-0295
    Pojawia się w:
    Wiadomości Chemiczne
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Badanie oddziaływania wankomycyny z fragmentem peptydoglikanu ściany komórkowej bakterii
    Study on interaction of vancomycin with bacterial cell wall peptidoglycan
    Autorzy:
    Samaszko-Fiertek, J.
    Ślusarz, R.
    Madaj, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/172720.pdf
    Data publikacji:
    2015
    Wydawca:
    Polskie Towarzystwo Chemiczne
    Tematy:
    wankomycyna
    wysokosprawna chromatografia cieczowa
    HPLC
    elektroforeza kapilarna
    magnetyczny rezonans jądrowy
    NMR
    SAMs
    vancomycin
    high performance liquid chromatography
    capillary electrophoresis
    nuclear magnetic resonance (NMR)
    self-assembled monolayers
    Opis:
    Unfortunately, despite of work involved in understanding of the mechanism of bacterial virulence, especially Staphylococcus aureus, it has not been developed effective therapy against this bacteria. The first antibiotic used against this bacteria was penicillin, which was discovered by Alexander Fleming in 1928. A new generation of drugs introduced into therapy against Staphylococcus aureus and other Gram-positive bacteria are glycopeptide antibiotics. The most widespread and most commonly used are vancomycin and teicoplanin, discovered respectively in 1956 and 1978. As a result of frequent use of vancomycin VISA (ang. Vancomycin-intermediate Staphylococcus aureus) and VRSA (ang. Vancomycin-resistant Staphylococcus aureus) strains were discovered. The mechanism of action of this antibiotic based on the inhibition of the biosynthesis of bacterial cell wall peptidoglycan fragment. Forming stabilized by hydrogen bonds complex with terminal fragment of peptidoglycan (dipeptide d-Ala-d-Ala) vancomycin prevents its further crosslinking [2] (Fig. 1). However, in recent years other theories of the mechanism of action of glycopeptide antibiotics against Gram-positive bacteria were presented it seems to be crucial to find methods of selection of new antibiotics and for this purpose standard techniques of the analysis, including isothermal titration calorimetry (ITC) [3], nuclear magnetic resonance spectroscopy (NMR) [8–15], high performance liquid chromatography (HPLC) [16], capillary electrophoresis [17] or self-assembled monolayers (SAMs) [22] are used. Discovering new methods for studying of interaction between vancomycin and Gram-positive bacterial cell wall allows use it as a new technique for rapid selection of potential new antibiotics, including glycopeptide derivatives.
    Źródło:
    Wiadomości Chemiczne; 2015, 69, 7-8; 491-511
    0043-5104
    2300-0295
    Pojawia się w:
    Wiadomości Chemiczne
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Zastosowanie soli chinoliniowych i pirydyniowych do oznaczania wybranych związków siarki w próbkach biologicznych
    Application of quinolinium and pyridinium salts for determination of selected sulfur compounds in biological samples
    Autorzy:
    Furmaniak, P.
    Wyszczelska-Rokiel, M.
    Kubalczyk, P.
    Głowacki, R.
    Powiązania:
    https://bibliotekanauki.pl/articles/171524.pdf
    Data publikacji:
    2014
    Wydawca:
    Polskie Towarzystwo Chemiczne
    Tematy:
    sole pirydyniowe
    sole chinoliniowe
    aminokwasy tiolowe
    derywatyzacja chemiczna
    chromatografia cieczowa
    wysokosprawna chromatografia cieczowa
    elektroforeza kapilarna
    pyridinium salts
    quinolinium salts
    thiol amino acids
    chemical derivatization
    high performance liquid chromatography
    capillary electrophoresis
    Opis:
    Quinolinium and pyridinium salts belong to the group of onium compounds and are widely used in organic, structural and analytical chemistry. Their synthesis is mainly based on quaternization of the nitrogen atom in a heterocyclic ring [4, 13, 23]. In analytical chemistry quinolinium and pyridinium salts such as 2-chloro-1-methylquinolinium tetrafluoroborate (CMQT) or 1-benzyl-2-chloropyridinium bromide (BCPB) perform very well as thiol specific derivatization reagents in terms of derivatization reaction velocity, stability, chromatographic properties of the derivatives, and thus, amenability to automatization [18–22, 32–42]. Analytical procedures for thiol determination usually involve reduction of disulfide bonds with tris(2-carboxyethyl)phosphine, tri-n-butylphosphine or mercaptoethanol, chemical derivatization of the sulfur compound with the use of 2-halopyridinium or 2-haloquinolinium salts and then deproteinization, followed by ion-pair reversed-phase HPLC or CE separation and spectrophotometric detection. Derivatization reaction takes advantage of great susceptibility of quinolinium or pyridinium molecules at 2-position to nucleophilic displacement, and a high nucleophilicity of the thiol group. Derivatization reaction mixture is usually ready to be analyzed just after mixing of the substrates. CMQT and BCPB exhibit very high reactivity toward thiols [44, 45], sulfides [63] as well as thiosulfates [40, 54]. 2-S-quinolinium and 2-S-pyridinium derivatives possess advantageous spectrophotometric and chromatographic properties. They are stable and more hydrophobic than thiols themselves, possessing a well-defined absorption maximum in the UV region. The reaction is accompanied by an analytically advantageous bathochromic shift from reagent maximum to the maximum of the derivative. Thanks to this phenomenon it is possible to use a large excess of derivatization reagent in order to drive the reaction to completion and avoid a huge signal of unreacted compound on the chromatogram [26]. Elaborated with the use of onium salts methods have proven to be useful in quantitative HPLC and CE analysis of endogenous and exogenous low-molecular-weight biological thiols in human body fluids, plant extracts and some groceries [44, 45].
    Źródło:
    Wiadomości Chemiczne; 2014, 68, 3-4; 211-232
    0043-5104
    2300-0295
    Pojawia się w:
    Wiadomości Chemiczne
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
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