Temat: Chromatografia - Katalog OPAC zbiorów

Skocz do pozycji: 1.

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

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Skocz do pozycji: 2.

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

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Skocz do pozycji: 3.

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

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Skocz do pozycji: 4.

Tytuł:: Spektrometria mas w badaniach skażeń mikrobiologicznych środowiska. Część 2, Kwasy 3-hydroksytłuszczowe jako biomarkery lipopolisacharydów (endotoksyn) ścian komórkowych bakterii gramujemnych
Investigetion (detection) of environment microbial contamination by mass spectrometry. Part 2, 3-hydroxy fatty acids as a lipopolysaccharides (endotoxin) biomarkers of the gram-negative bacterial cell walls
Autorzy:: Bal, K.
Mielniczuk, Z.
Powiązania:: https://bibliotekanauki.pl/articles/172406.pdf
Data publikacji:: 2016
Wydawca:: Polskie Towarzystwo Chemiczne
Tematy:: LPS
lipopolisacharyd
chromatografia gazowa
spektrometria mas
lipopolysaccharide
gas chromatography
mass spectrometry
Opis:: Microorganisms synthesize several monomeric chemical structures that are not found elsewhere in nature, e.g. muramic acid (an amino sugar) and D-amino acids (D-alanine and D-glutamic acid) are ubiquitous in bacterial peptidoglycan (PG). Characteristic sugars (e.g. heptoses) and 3-hydroxylated fatty acids are found in the endotoxin (lipopolysaccharide, LPS) of gram-negative bacteria [1]. The best way to protect against environment contamination is microbial control. Methods in current use for monitoring microorganisms mainly include culture and direct microscopy. However, several factors, including samples collection, growth conditions, incubation temperature and interaction between different organisms all affected the culture results. Additionally, culture based methods can detect only viable organisms and they are also time consuming, sometimes taking days or weeks. However, since both living and dead microorganisms express irritating and toxic structures, they should all be taken into consideration. Muramic acid has been suggested for use as a chemical marker in gas chromatography-mass spectrometry (GC-MS) determination of bacterial peptidoglycan [2]. While 3-hydroxylated fatty acids are the best proposition for use as a chemical markers in gas chromatography-mass spectrometry determination of bacterial lipopolysaccharide (endotoxin) of gram-negative bacteria in both clinical and environmental samples [38]. Two derivatives have been applied, including the trimethylsilyl (TMS) and pentafluorobenzoyl (PFBO) derivatives [80]. Both derivatives (TMS and PFBO) have been proven suitable for use with GC-ion-trap tandem MS [3]. The aim of our proposition is trial of application of gas chromatography-mass spectrometry (GC-MS) method as an alternative or complement to culturing, microscopy and other assays for detection, characterization and monitoring of microbial contamination of environment (e.g. water, air, air-conditioning systems), contamination of biochemical and food production chain processes, packaging for foodstuffs etc. by analysis of bacterial 3-hydroxylated fatty acids as a biochemical markers. A method is described for the quantitation of methyl esters of 3-hydroxyacids, markers of bacterial lipopolysaccharide (endotoxin), as trimethylsilyl or pentafluorobenzoyl derivatives using GC/MS method. The described methods are quick and simple, can be applied for monitoring microbial contamination directly, without prior culturing, in complex environmental samples. This method can be also applied for testing processes of cleaning and disinfections on packaging materials or on both packaging materials/foodstuffs in order to decrease their microbial load and thus to ensure better shelf-life. [1] Z. Mielniczuk, K. Bal, Spektrometria mas w badaniach skażeń mikrobiologicznych środowiska. Część I. Kwas muraminowy jako biomarker ścian komórkowych bakterii, Wiad. Chem., 2012, 66, 445. [2] K. Bal, L. Larsson, E. Mielniczuk, Z. Mielniczuk, Structure of muramic acid TMS derivative mass spectrum’s base ion (m/z=185) used for quantification of bacterial peptidoglycan, J. Microbiol. Meth., 2002, 48, 267. [3] A. Saraf, L. Larsson, Identification of microorganisms by mass spectrometry, Advances in Mass Spectrometry, 1998, 14, 449. [38] Z. Mielniczuk, E. Mielniczuk, L. Larsson, Gas chromatography-mass spectrometry methods for analysis of 2- and 3-hydroxylated fatty acids: Application for endotoxin measurement, J. Microbiol. Meth., 1993, 17, 91. [80] Z. Mielniczuk, S. Alugupalli, E. Mielniczuk, L. Larsson, Gas chromatography-mass spectrometry of lipopolysaccharide 3-hydroxy fatty acids: comparison of pentafluorobenzoyl and trimethylsilyl methyl ester derivatives, J. Chromatogr., 1992, 623, 115.
Źródło:: Wiadomości Chemiczne; 2016, 70, 1-2; 95-117
0043-5104
2300-0295
Pojawia się w:: Wiadomości Chemiczne
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Metody badań niejednorodności energetycznej powierzchni katalizatorów i adsorbentów
Methods of investigation energetical heterogeneity on the surface of catalysts and adsorbents
Autorzy:: Woszczyński, P.
Powiązania:: https://bibliotekanauki.pl/articles/172199.pdf
Data publikacji:: 2013
Wydawca:: Polskie Towarzystwo Chemiczne
Tematy:: heterogeniczność
niejednorodność energetyczna
równanie Fredholma
adsorpcja
kalorymetria
chromatografia
odwrócona chromatografia gazowa
chromatografia z odwróconym przepływem
programowana termiczna desorpcja
heterogeneity
adsorbent
catalyst
Fredholm equation
adsorption
calorimetry
chromatography
inverse gas chromatography (IGC)
IGC
reverse-flow IGC (RF-IGC )
programmed thermal desorption (TPD)
TPD
Opis:: The knowledge of the properties and a surface structure of catalysts and adsorbents is of great importance in the selection of these materials to the relevant objectives. Interesting structural information can be obtained in many ways, for example: with the use of spectroscopic or microscopic techniques or in direct examination of the adsorption isotherms. This article focuses on these last-mentioned methods, which can be a source of information on energy heterogeneity of the catalyst or adsorbent surface. Heterogeneity is usually determined by measuring adsorption isotherms of a selected adsorbate on the examined adsorbent, which is dependent of adsorbate coverage on the adsorbent relative to the equilibrium pressure under isothermal conditions. Among the many mathematical models describing this relationship particularly interesting is the adsorption isotherm model described by generalized integral Fredholm equation. The solution of this equation is density function with the assumed local isotherm model. There are different ways to solve the Fredholm equation, depending on measurement methods of obtained adsorption isotherms. For example, an application of static techniques (gravimetric or volumetric) needs to use advanced, sophisticated numerical methods for directly solving integral equations, other techniques (e.g. such as calorimetric or chromatographic) provide specific values that simplify these calculations. The resulting energy density function allows to observe active centers as peaks or inflections of the curve on the energy spectrum graph.
Źródło:: Wiadomości Chemiczne; 2013, 67, 7-8; 635-664
0043-5104
2300-0295
Pojawia się w:: Wiadomości Chemiczne
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

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

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Skocz do pozycji: 7.

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

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Skocz do pozycji: 8.

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

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Skocz do pozycji: 9.

Tytuł:: Spektrometria mas w badaniach skażeń mikrobiologicznych środowiska . Część I. Kwas muraminowy jako biomarker ścian komórkowych bakterii
Investigation (detection ) of microbal environmental contamination by mass spectrometry. Part I. Muramic acid as a biomarker of the microbial cell walls
Autorzy:: Mielniczuk, Z.
Bal, K.
Powiązania:: https://bibliotekanauki.pl/articles/172533.pdf
Data publikacji:: 2012
Wydawca:: Polskie Towarzystwo Chemiczne
Tematy:: kwas muraminowy
peptydoglikan
chromatografia gazowa
spektrometria mas
muramic acid
peptidoglycan
gas chromatography-mass spectrometry
Opis:: Microorganisms synthesize several monomeric chemical structures that are not found elsewhere in nature, e.g. muramic acid (an amino sugar) and D-amino acids (D-alanine and D-glutamic acid) are ubiquitous in bacterial peptidoglycan (PG). Specific sugars (e.g. heptoses) and 3-hydroxylated fatty acids are found in the endotoxin (lipopolysaccharide, LPS) of gram-negative bacteria [42]. The best way to protect against environmental contamination is microbial control. Methods in current use for monitoring of microorganisms mainly include culturing and direct microscopy. However, several factors including samples collection, growth conditions, incubation temperature and interaction between different organisms all affect culturing results. Additionally, culturing based methods can detect only viable organisms and they are also time consuming, sometimes taking days or weeks. However, since both living and dead microorganisms express irritating and toxic structures, they should all be taken into consideration [17]. Muramic acid (MuAc), an amino sugar, has been suggested for use as a chemical marker in gas chromatography-mass spectrometry (GC-MS) determination of bacterial peptidoglycan in both clinical and environmental samples. Several derivatives of MuAc have been applied, including the alditol acetate [1, 2], aldononitrile [3], trifluoroacetyl [4] and trimethylsilyl [5], and methyl ester O-methyl acetate [6] derivatives. Both the alditol acetate and TMS derivatives have proven suitable for the use with GC-ion-trap tandem MS [7]. The aim of our proposition is a trial of application of gas chromatography-mass spectrometry (GC-MS) method as an alternative or complement to culturing, microscopy and other assays for detection, characterization and monitoring of microbial contamination of environment (e.g. water, air, air-conditioning systems), contamination of biochemical and food production chain processes, packaging for foodstuffs etc. by direct analysis of bacterial muramic acid as a biochemical marker. A method is described for the quantitation of muramic acid, a marker of bacterial peptidoglycan as trimethylsilyl (TMS ) derivatives using GC/MS method. The described methods are fast and simple, and can be applied for monitoring of microbial contamination directly, without prior culturing, in complex environmental samples. This method can also be applied for testing processes of cleaning and disinfection on packaging materials or on both packaging materials/foodstuffs in order to decrease their microbial load and thus to ensure better shelf-life.
Źródło:: Wiadomości Chemiczne; 2012, 66, 5-6; 445-460
0043-5104
2300-0295
Pojawia się w:: Wiadomości Chemiczne
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

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

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Skocz do pozycji: 11.

Tytuł:: Proces samo-dysproporcjowania enancjomerów podczas chromatografii kolumnowej
Self-disproportionation of enantiomers via column chromatography
Autorzy:: Wzorek, Alicja
Kwiatkowska, Magdalena
Urbaniak, Mariusz
Gawdzik, Barbara
Powiązania:: https://bibliotekanauki.pl/articles/27310046.pdf
Data publikacji:: 2023
Wydawca:: Polskie Towarzystwo Chemiczne
Tematy:: chiralność
chromatografia
asocjacja
enancjomeryczne wzbogacanie
oddziaływania międzycząsteczkowe
chirality
chromatography
association
enantiomeric enrichment
intermolecular interactions
Opis:: The review is devoted to self-disproportionation of enantiomers (SDE) phenomenon which has been observed for many different classes of chiral organic compounds. The SDE phenomenon occurs when the fractionation of an enantioenriched sample due the application of a physicochemical process under achiral conditions results in the variation of the proportion of the enantiomers present across the fractions, though the overall composition in terms of the sample ee remains unchanged. The SDE process can be considered in terms of separating the excess enantiomer from the racemate. The basic terminology related to SDE was described. The formation of the SDE under chromatographic conditions is the result of an association process occurring in a solution of a chiral, non-racemic compound. Information on preferred interactions leading to homo-/heterochiral supramolecules can be provided by quantum chemical calculations, NMR spectroscopy and comparison of crystal structures of the racemic and enantiomeric crystals. Several examples of the chromatographic experiments with different classes of compounds were given in two purposes 1) to highlight the possibility of application SDE during column chromatography as the method for enantiopurification of the chiral, non-racemic compounds; 2) to demonstrate that a standard workup (chromatographic purification, evaporation) can alter the stereochemical outcome of asymmetric reactions.
Źródło:: Wiadomości Chemiczne; 2023, 77, 5-6; 425--448
0043-5104
2300-0295
Pojawia się w:: Wiadomości Chemiczne
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 12.

Tytuł:: Wybrane metody separacyjne i woltamperometryczne w analizie leków i substancji endogennych dla diagnostyki i terapii klinicznej
Selected separation and voltammetric methods in the analysis of drugs and endogenous substances for diagnostics and clinical therapy
Autorzy:: Baranowska, Irena
Bajkacz, Sylwia
Markowski, Piotr
Płonka, Joanna
Powiązania:: https://bibliotekanauki.pl/articles/1413240.pdf
Data publikacji:: 2021
Wydawca:: Polskie Towarzystwo Chemiczne
Tematy:: chromatografia
woltamperometria
leki
aminy biogenne
ekstrakcja
spektrometria
chromatography
voltammetry
drugs
biogenic amines
extraction
spectrometry
Opis:: The developed chromatographic methods (HPLC and UHPLC/UV, DAD, FL, ED, MS-MS and GC-MS), for the determination of drugs from different therapeutic groups in body fluids, have been presented. Drugs were determined alongside their metabolites, in different concentration ranges, usually after a removal of the interferences from the biological material matrix. Extraction procedures, like LLE, SPE, MEPS, SALLE, USAEME, have been developed for the separation of analytes. Methods for the determination of endogenous compounds: L-camitine, L-arginine and their metabolites, dopamine and its metabolites, and other compounds resulting from their metabolism have also been developed. Cyclic voltammetry and differential pulse voltammetry methods for the determination of electrochemically active drugs have also been presented. Such methods can be used to verify the results of chromatographic determinations. This article presents the results of the research included in 35 publications from the JCR list.
Źródło:: Wiadomości Chemiczne; 2021, 75, 7-8; 869-892
0043-5104
2300-0295
Pojawia się w:: Wiadomości Chemiczne
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 13.

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

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Skocz do pozycji: 14.

Tytuł:: Metody analityczne badania preparatów kosmetycznych - wczoraj i dziś
Analitical methods for testing cosmetic products - in the past and nowadays
Autorzy:: Olejnik, Anna
Gornowicz-Porowska, Justyna
Gościańska, Joanna
Powiązania:: https://bibliotekanauki.pl/articles/2200575.pdf
Data publikacji:: 2022
Wydawca:: Polskie Towarzystwo Chemiczne
Tematy:: produkty kosmetyczne
chromatografia
spektrometria mas
test aplikacyjny
badania stabilności
cosmetic products
chromatography
mass spectrometry
application test
stability studies
Opis:: The safety and quality of each cosmetic product is tested before it is introduced to the market. There are highly regulated requirements that producers should comply with. However, as the cosmetic products are highly complexed mixture of different ingredients, detailed characterization of their composition remains still a challenge. Currently, due to the development of modern technologies, a wide range of analytical methods are available. Scientists are increasingly adapting highly sophisticated and advanced techniques to precisely identify and quantify the components of cosmetic products. The aim of this article is to present the analytical methods applied to examine cosmetics taking into account their advantages and limitations. The progress made in recent years in the design of novel instruments leading to their greater efficiency, selectivity and sensitivity was also considered. The techniques that are commonly used in the quality control laboratories of cosmetic companies were presented. Cosmetics analysis is not only limited to the characterization of product itself. Today, in vivo tests are very essential to determine the efficacy of formulations directly on the skin surface. Therefore, in this article modern devices dedicated to theses analyses were described in detail.
Źródło:: Wiadomości Chemiczne; 2022, 76, 7-8; 607--633
0043-5104
2300-0295
Pojawia się w:: Wiadomości Chemiczne
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 15.

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

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