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Wyniki wyszukiwania dla: liquid chromatography
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Liquid chromatography techniques for separation of flavonoids from Droseraceae
PublikacjaFlavonoids which are presented in insectivorous plants of the Droseraceae family have wide range of advantageous properties i.e. an antioxidant, anti-inflammatory and antimicrobial activities, antitumor activity was reported as well.The purpose of the research was to develop the most favourable conditions for liquid chromatographic separation and identification of myricetin and quercetin in extracts of insectivorous plants. In...
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Free silanols and ionic liquids as their suppressors in liquid chromatography
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Calixarenes as stationary phases in High Performance Liquid Chromatography
PublikacjaPraca przeglądowa przedstawia dotychczasowe metody syntezy faz stacjonarnych na bazie pochodnych kaliksarenów, kaliksrezorcyarenów i kalikspiroli chemicznie ziązanych z żelem krzemionkowym lub dynamicznie na nim obsadzonych. Podsumowano zastosowanie tych faz w rozdzielaniu szeregu klas związków organicznych i nieorganicznych metodą wysokosprawnej chromatografii cieczowej.
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pH gradient high-performance liquid chromatography: theory and applications
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In-Syringe Dispersive Liquid-Liquid Microextraction Coupled with High- Performance Liquid Chromatography for Trace Analysis of Naphthalene Sulfonates in Seawater
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Quantitative structure–retention relationships in affinity high-performance liquid chromatography
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The simultaneous determination of hydrophobicity and dissociation constant by liquid chromatography–mass spectrometry
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Application of normal-phase high-performance liquid chromatography followed by gas chromatography for analytics of diesel fuel additives
PublikacjaThe paper presents the results of investigations on new procedures of determination of selected cleaning additives in diesel fuel. Two procedures: one-step analysis using gas chromatography with flame ionization detection (GC-FID) or mass spectrometry (GC-MS) and a two-step procedure in which normal-phase high-performance liquid chromatography (NP-HPLC) was used for preliminary separation of the additives, were compared. The additive...
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Application of normal-phase high-performance liquid chromatography followed by gas chromatography for analytics of diesel fuel additives
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Size Exclusion Coupled to Reversed Phase Liquid Chromatography for the Characterization of Cranberry Products
PublikacjaA combination of solvent extraction, size exclusion purification, and reversed-phase liquid chromatography with UV absorption and fluorescence detection was here used for the determination of flavan-3-ols and related oligomeric compounds in cranberry products. The method relied on robust, simple, and inexpensive instrumental equipment present in most of routine analytical laboratories. Sample extracts in methanol/water/hydrochloric...
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High resolution liquid chromatography and time of flight mass spectrometry in perfume analysis
PublikacjaPerfumes consist of a wide range of natural and synthetic compounds that belongs to different chemical classes. Most of these compounds are generally determined by GC. However, in this study RP-HPLC-Q-TOF-MS and HILIC-Q-TOF-MS technique was applied for the determination of ingredients of original perfumes and their imitations. Antioxidants and compounds specific to fragrances of animal \origin were found in original...
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Determination of hormones in water samples using liquid chromatography coupled with tandem mass spectrometry
PublikacjaOver the past few years, many synthetic (ethinylestradiol) and natural (estradiol,estriol, estrone) compounds present in the environment have been affecting the hormonalbalance of humans and animals. Steroid hormones are very often used for medical purposesand have high estrogenic activity what makes them endocrine disrupters. Most hormonalcompounds are released into the water as a result of their incomplete removal in wastewatertreatment...
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Polyfunctional chemically bonded stationary phase for reversed phase high-performance liquid chromatography
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Liquid chromatography tandem mass spectrometry study of urinary nucleosides as potential cancer markers
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Suppression of deleterious effects of free silanols in liquid chromatography by imidazolium tetrafluoroborate ionic liquids
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Comparative study of surface topography of high performance liquid chromatography columns in terms of hydrophobicity
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Characterization of In Vitro and In Vivo Metabolism of Antazoline Using Liquid Chromatography-Tandem Mass Spectrometry
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Troubleshooting of the determination of bisphenol A at ultra-trace levels by liquid chromatography and tandem mass spectrometry
PublikacjaDetermination of trace amounts of bisphenol A (BPA) may cause problems mainly related to the presence of BPA in solvents (even in LC-MS grade), laboratory vessels, and plastic equipment used for sample preparation. Variable and sometimes significant amounts of BPA present in the background cause problems in obtaining good repeatability of measurements at the ultra-trace levels. Such observations (i.e., poor repeatability of results)...
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Optimal conditions of naphthoquinones separation from carnivorous plants extracts using thin-layer chromatography and high performance liquid chromatography
PublikacjaDroseraceae plants are owned by the family of carnivorous plants, which in an unusual way adapt to environments poor in nutrients. Droseraceae obtain essential nutrients catching insects and other small invertebrantes. Plumbagin, chloroplumbagin, ramentaceon and droseron are naphthoquinones, which could be found in leaves and shoots of plants from Droseraceae family. In the literature there are a lot of information about the pharmacological...
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DETERMINATION OF POLYCYCLIC AROMATIC HYDROCARBONS IN SOIL SAMPLES USING ULTRASONIC PROBE AND SALT-ASSISTED LIQUID-LIQUID EXTRACTION COUPLED WITH HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY
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“Dilute & Shoot” approach for rapid determination of trace amounts of nicotine in zero-level e-liquids by reversed phase liquid chromatography and hydrophilic interactions liquid chromatography coupled with tandem mass spectrometry-electrospray ionization
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“Dilute & Shoot” approach for rapid determination of trace amounts of nicotine in zero-level e-liquids by reversed phase liquid chromatography and hydrophilic interactions liquid chromatography coupled with tandem mass spectrometry-electrospray ionization
PublikacjaTwo analytical procedures are proposed where HILIC and RPLC techniques are coupled with tandem mass spectrometry detection for rapid determination of trace amounts of nicotine in zero-level liquids for electronic cigarettes. Samples are prepared on the basis of the approach “dilute & shoot” which makes this important step quick and not complicated. The chromatographic separation was carried out on a Zorbax XDB column (RPLC method)...
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A research on the optimal conditions for separation and identyfication of the components from the Droseraceae extracts by column liquid chromatography
PublikacjaThe isolation of the components with anticipated biological properties i.e. antimicrobial, fungicidal, antioxidant and perhaps anticancer activity is for many years a one of the biggest issues of modern separation science. Their obtaining based on the isolation of the components with the biological activity from in vitro cultured plants by extraction techniques is often more difficult than their production by the chemical synthesis.The...
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Comprehensive methodology for Staphylococcus aureus lipidomics by liquid chromatography and quadrupole time-of-flight mass spectrometry
PublikacjaStaphylococcus aureus is a common pathogen known to cause relatively minor infections as well as severe disorders in humans. Although there is fair amount of published data concerning various aspects of its biology, epidemiology, genetics, etc., there is still a scarce amount of data presenting reliable and thorough investigations regarding high-throughput analysis of total S. aureus lipid content. Therefore, the aim of this study...
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Determination of isoprostanes in exhaled breath condensate samples by liquid chromatography coupled with tandem mass spectrometry
PublikacjaOxidative stress (OS) is a state of imbalance between continuously generating reactive oxygen species (ROS) during normal cell metabolism and mechanism of detoxifying oxygen radicals through a network of antioxidative enzymes. Isoprostanes are prostaglandin -like substances that are produced in vivo primarily by free radical-induced peroxidation of arachidonic acid. The measurement of isoprostanes in biological fluids and/or tissue...
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Study of pH and temperature effect on lipophilicity of catechol-containing antioxidants by reversed phase liquid chromatography
PublikacjaLipophilicity of selected antioxidant phytochemicals, including flavonoids, phenolic acids and xanthonoids, was determined by reversed phase high performance liquid chromatography with UV detection (RP-HPLC-UV). The analyses run at different temperature and pH conditions in isocratic mode suggested that lipophilicity as distribution coefficient (logD) between aqueous and organic phase decreases with increasing temperature. For...
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Determination of high-intensity sweeteners in beverages by high-performance liquid chromatography with mass spectrometry detection.
PublikacjaThe objective of the present study was to measure the concentration of nine high intensity sweeteners (acesulfame-K, aspartame, alitame, cyclamate, dulcin, neohesperidin dihydrochalcon, neotame, saccharin and sucralose) in different types of beverages available on the polish market. The proposed methodology reported here consists of a extraction with buffer composed of formic acid and N,N-diisopropylethylamine (pH 4.5) followed...
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Lipophilicity data for some preservatives estimated by reversed-phase liquid chromatography and different copmutation methods
PublikacjaW pracy przedstawiono wyniki badań właściwości chromatograficznych wybranych 12 związków z grupy kopnserwantów. Lipofilowy charakter tych związków był oceniany na podtsawie różnych parametrów retencyjnych (log Kw, log K i inne. Zastosowano narzędzie chemometryczne do zbadania korelacji występujących pomiędzy tymi parametrami retencji chromatogfraficznej.
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The lipophilicity indices of flavonoids estimated by reversed-phase liquid chromatography using different computation methods
PublikacjaDo oceny właściwości chromatograficznych wybranych flawonoidów zastosowano wyskokosprawną chromatografię cieczową z odwróconym układem faz i kolumnami chromatograficznymi typu C-8 i C-18.Lipofilowość wyrażono za pomocą różnych deskryptów lipofilowości.
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The application of gradient reversed-phase high-performance liquid chromatography to the pKa and determination of polyprotic analytes
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High-performance liquid chromatography in group-type separation and technical or process analytics of petroleum products
PublikacjaW pracy dokonano przeglądu i poddano krytycznej ocenie metody oznaczania składu grupowego produktów naftowych o różnej lotności, zarówno metody znormalizowane, jak i opisane w literaturze naukowej. W zdecydowanej większości są to metody wykorzystujące technikę chromatografii cieczowej w układzie faz normalnych (NP-HPLC). Na podstawie danych z literatury oraz własnych studiów i badań należy stwierdzić, że im wyższy zakres temperatury...
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Uncertainty of antioxidant profiling in complex mixtures using liquid chromatography involving post-column derivatisation
PublikacjaThe main goal of this paper is to discuss the problems associated with antioxidant profiling in complex samples using a high-throughput HPLC system coupled with post-column derivatisation reactor. Based on the experimental data reported in the literature, we demonstrated that improper optimisation of temperature and/or pH assay conditions performed using an on-line derivatisation reactor may substantially change the antioxidant...
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Sensitive determination of isoprostanes in exhaled breath condensate samples with use of liquid chromatography-tandem mass spectrometry
PublikacjaOxidative stress is the hallmark of various inflammatory lung diseases. Increased concentrations of reactive oxygen species in the lungs are reflected by elevated concentrations of oxidative stress markers in the breath, airways, lung tissue and blood. The aim of this work was to develop a method for the fast measurement of F2 isoprostanes in exhaled breath condensate (EBC) samples using equipment which is nowadays available and...
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Comparison of High Performance Liquid Chromatography Methods with Different Detectors for Determination of Steroid Hormones in Aqueous Matrices
PublikacjaThis paper presents the development and comparison of procedures for the qualitative and quantitative determination of five estrogenic compounds (17-a-ethynylestradiol, estrone, estradiol, estriol, and progesterone) in drinking water and wastewater samples. Five extraction columns and two disks were tested for their efficiency. The C18 columns were superior on the basis of cost for solid phase extraction of drinking water or sewage....
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Sensitive determination of isoprostanes in exhaled breath condensate samples with use of liquid chromatography–tandem mass spectrometry
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Retention time and peak width in the combined pH/organic modifier gradient high performance liquid chromatography
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Effect of sample-preparation methods on the quantification of selected flavonoids in plant materials by high performance liquid chromatography
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Determination of nine high-intensity sweeteners in various foods by high-performance liquid chromatography with mass spectrometric detection
PublikacjaAn analytical procedure involving solid-phase extraction (SPE) and high-performance liquid chromatography-mass spectrometry has been developed for the determination of nine high-intensity sweeteners authorised in the EU; acesulfame-K (ACS-K), aspartame (ASP), alitame (ALI), cyclamate (CYC), dulcin (DUL), neohesperidin dihydrochalcone (NHDC), neotame (NEO), saccharin (SAC) and sucralose (SCL) in a variety of food samples (i.e. beverages,...
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Analysis of multi-class pharmaceuticals in fish tissues by ultra-high-performance liquid chromatography tandem mass spectrometry
PublikacjaA new sensitive method based on pressurized liquid extraction (PLE) and purification by gel permeation chromatography (GPC) prior to ultra-high-performance liquid chromatography coupled to tandem mass spectrometry (UHPLC–MS/MS) was developed for the determination in fish homogenate, liver and muscle of twenty pharmaceuticals compounds and metabolites from seven commonly used therapeutic families. An extensive matrix effect evaluation...
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Development of a liquid chromatography–tandem mass spectrometryprocedure for determination of endocrine disrupting compounds infish from Mediterranean rivers
PublikacjaA new, sensitive and rapid method based on QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe)approach followed by ultra high performance liquid chromatography coupled with tandem mass spec-trometry (UHPLC–MS/MS) was developed for the determination of nineteen endocrine disruptors (EDCs)and related compounds belonging to different classes in various fish species. Matrix effect on the analyti-cal performance was evaluated,...
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Determination of tocopherols and tocotrienols in human breast adipose tissue with the use of high performance liquid chromatography-fluorescence detection
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Process control of leakages in refinery reforming plant by means of Normal Phase High Performance Liquid Chromatography (HPLC)
PublikacjaPraca dotyczy zbadania możliwości, opracowania nowej procedury badawczej oraz dokonania oznaczeń ¬m-krezolu w strumieniu produktu z procesu reformingu katalitycznego techniką wysokosprawnej chromatografii cieczowej w układzie faz normalnych, z detektorem spektrofotometrycznym typu DAD (NP-HPLC-UV-VIS/DAD). Opracowana procedura stanowi alternatywę dla innych procedur wykorzystujących klasyczne techniki analityczne, albo wykorzystanie...
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Determination of flavanols by liquid chromatography with fluorescence detection. Application to the characterization of cranberry-based pharmaceuticals through profiling and fingerprinting approaches
PublikacjaIn this work, a new method based on reversed-phase high-performance liquid chromatography (HPLC) with fluorescence detection (FLD) was established for the determination of catechins and related oligomeric proanthocyanidins (PACs) in cranberry-based pharmaceuticals. Compounds were recovered by liquid extraction using methanol/water/hydrochloric acid (60:39:1, v:v:v) as the extraction solvent. The chromatographic separation was carried...
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An evaluation of sucrose as a possible contaminant in e-liquids for electronic cigarettes by hydrophilic interaction liquid chromatography–tandem mass spectrometry
PublikacjaThe influence of sucrose combustion products on smoking and nicotine addiction is still controversial because the presence of the sucrose may be treated as a source of aldehydes and organic acids. In e-liquids used as refills for electronic cigarettes, which are made primarily of poly(propylene glycol), glycerine and ethanol, sucrose may be present at trace levels, and its impact on mainstream smoke formation, and hence on human...
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Determination of Pesticide Residues in Honeybees using Modified QUEChERS Sample Work-Up and Liquid Chromatography-Tandem Mass Spectrometry
PublikacjaIncreasing emissions of chemical compounds to the environment, especially of pesticides, is one of factors that may explain present honeybee colony losses. In this work, an analytical method employing liquid chromatography-tandem mass spectrometry (LC-MS/MS) was optimized for the simultaneous screening of 19 pesticides which have not been yet determined in honeybee samples from northern Poland (Pomerania). The sample preparation,...
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An evaluation of sucrose as a possible contaminant in e-liquids for electronic cigarettes by hydrophilic interaction liquid chromatography–tandem mass spectrometry
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Determination of Nine Intense Sweeteners in Foodstuffs by High-Performance Liquid Chromatography and Evaporative Light-Scattering Detection: Interlaboratory Study
PublikacjaW pracy przedstawiono wyniki badań międzylaboratoryjnych, opracowanej wcześniej metody jednoczesnego oznaczania dziewięciu słodzików o wysokiej mocy w produktach żywnościowych. W badaniach wzięło udział siedem laboratoriów (Belgia, Niemcy, Portugalia). W rezultacie dowiedziono, iż opracowana metoda umożliwia uzyskanie dokładnych, powtarzalnych i odtwarzalnych wyników analiz dla wszystkich badanych słodzików i typów żywności.
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Partition coefficients of selected environmentally important volatile organic compounds determined by gas - liquid chromatography with polydimethylsiloxane stationary phase
PublikacjaPrzedstawiono wartości współczynników podziału (stałych podziału) 14 lotnych związków organicznych istotnych dla stanu środowiska (często oznaczanych w powietrzu w pomieszczeniach zamkniętych) między fazą gazową (N2) a ciekłą (PDMS). Wyznaczano je dwiema technikami (izotermiczną i z liniowo programowanym wzrostem temperatury). Dowiedziono, że istnieje możliwość wyznaczania współczynników podziału techniką LTPRI w oparciu o skalę...
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Determination of nonsteroidal antiinflammatory drugs in water samples using liquid chromatography coupled with diode-array detector and mass spectrometry
PublikacjaOpracowano i zwalidowano metodykę do oznaczania śladowych ilości sześciu różnych związków z grupy niesteroidowych leków przeciwzapalnych w próbkach wodnych. Anality zostały wybrane spośród najczęsciej sprzedawanych leków w Polsce. Sprawdzono kilka różnych kolumienek ekstrakcyjnych i wybrano RP-18 jako najlepsze wypełnienie do wzbogacania oznaczanych związków. Opracowaną metodykę z powodzeniem zastosowano do analizy próbek rzeczywistych.
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Direct injection liquid chromatography-mass spectrometry (DI-LC-MS) analysis for rapid lipidomic profiling of extracellular vesicles
PublikacjaExtracellular vesicles (EVs) are small, spherical particles produced by eukaryotic and prokaryotic cells, surrounded by a bilayer membrane and carrying various bioactive molecules, such as proteins, surface receptors, membrane and soluble proteins, lipids, and nucleic acids. EVs are of substantial interest because of their important roles in cell communication, epigenetic regulation and possible application in disease diagnosis...