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Search results for: CHEMICAL COMPOSITION
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Uncertainty of antioxidant profiling in complex mixtures using liquid chromatography involving post-column derivatisation
PublicationThe 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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HPLC-coupled post-column derivatization aims at characterization and monitoring of plant phytocomplexes, not at assessing their biological properties
PublicationTwo recent decades of research identified a number of environmental factors as well as mechanisms leading to pathogenic processes in the human organism. A common factor in pathogenesis of many diseases is oxidative stress, a condition in which the production of damaging reactive oxygen species (ROS), present in the body as an inevitable consequence of respiration and exacerbated by the inflammatory response and by exogenous factors...
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Comparison of the contents of bioactive compounds and the level of antioxidant activity in different kiwifruit cultivars
PublicationGłównym celem prowadzonych badań było stwierdzenie która z odmian owoców kiwi (''Hayward'', ''Daeheuhg'', ''Haenam'' oraz ''Bidan'') jest najbardziej odpowiednią z punktu widzenia konsumpcji przez człowieka. Z tego powodu w odpowiednio przygotowanych próbkach ekstraktów z owoców kiwi oznaczono:- profile związków bioaktywnych;- poziomy aktywności przeciwutleniającej. Wyniki pomiarów zawartości polifenoli (flawonoidy oraz kwasy fenolowe)...
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Combination of homogeneous liquid–liquid extraction and vortex assisted dispersive liquid–liquid microextraction for the extraction and analysis of ochratoxin A in dried fruit samples: Central composite design optimization
PublicationThis paper presents a new analytical procedure based on combination of homogeneous liquid–liquid extraction (HLLE) and vortex-assisted dispersive liquid–liquid microextraction (VA-DLLME) for the accurate and reliable determination of ochratoxin A (OTA) in dried fruit samples. To enable selective extraction of the OTA, six hydrophobic deep eutectic solvents (hDESs) were prepared and tested as extraction solvents. Optimization of...
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Application of chemometric modeling for ionic liquid-based ultrasonic-assisted dispersive liquid-liquid microextraction: Analysis of fosetyl-aluminum in fruit and vegetable samples
PublicationThis manuscript presents a new method for selective extraction and determination of fosetyl-aluminum in fruits and vegetable samples based on ultrasonic-assisted dispersive liquid-liquid microextraction method using ionic liquids (IL-UA-DLLME). A UV-Visible spectrophotometer was used for detection and quantification. Plants used for sample collection were grown under controlled conditions in a greenhouse. Central composite design...
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Magnetic hydrophobic deep eutectic solvents for orbital shaker-assisted dispersive liquid-liquid microextraction (MAGDES-OS-DLLME) - determination of nickel and copper in food and water samples by FAAS
PublicationIn this work, a cheap and widely applicable dispersive liquid-liquid microextraction (DLLME) method was developed for the extraction of Ni(II) and Cu(II) from water and food samples and analysis using flame atomic absorption spectrometry. DLLME was assisted by orbital shaker, while ferrofluid as an extractant was based on deep eutectic solvent (DES). This ferrofluid was made of hydrophobic DES (hDES), composed of lauric acid and...
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Quality control of cheese samples for the presence of natamycin preservative – A natural deep eutectic solvent (NADES) based extraction coupled with HPLC
PublicationA new protocol for the determination of natamycin – an antifungal agent used as a food preservative - in cheese samples – is described. This new method is based on a natural deep eutectic solvent (NADES) green extraction procedure. High-performance liquid chromatography (HPLC) was used for detection and quantification. NADESs with different molar ratios were evaluated for efficient and selective extraction. NADES made of thymol...
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Optimization of vortex-assisted supramolecular solvent-based liquid liquid microextraction for the determination of mercury in real water and food samples
PublicationA novel method was developed for sample preparation for spectrophotometric determination of Hg(II) in water and food samples. The method was based on vortex-assisted supramolecular solvent-assisted liquid-liquid microextraction (VA-SUPRASs-LLME). Analytical parameters such as pH, chelating agent, solvent type and volume, vortex time and salting out effect were optimized. Surface and normal probability plots were drawn for the variables...
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A comprehensive lipidomic analysis of oilseeds using LC-Q-TOF-MS and dispersive micro-solid phase (D-μ-SPE) extraction techniques
PublicationGrowing public health awareness increased the demand for natural products with positive health benefits. Vegetable oils containing omega-3 fatty acids (FA) such as alpha-linolenic acid (ALA) has been proposed as a possible source of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). In this work, a comprehensive lipidome analysis and comparison of seven oilseeds, including flaxseed, chia, hemp, black cumin, white sesame,...
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Extraction and Analysis of Bisphenols and Their Derivatives in Infant and Toddler Ready-to-feed Meals by Ultrasound-assisted Membrane Extraction Followed by LC MS/MS
PublicationThis research developed an ultrasound-assisted membrane extraction coupled with liquid chromatography-tandem mass spectrometry method for the determination of nineteen bisphenols and their derivatives in infant and toddler ready-to-feed meals. The calibration curves for all analytes were linear in the tested range, and the limit of detection and limit of quantitation were in the range 0.27 to 0.79 ng/g and 0.80 to 2.4 ng/g, respectively....
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Ionogel sorbent coatings for determining organophosphorus and pyrethroid insecticides in water and fresh juice samples by headspace-solid phase microextraction
PublicationThe sol–gel method yielded three different ionogel sorbent coatings that were obtained based on a silica material containing ionic liquids (ILs) immobilized in its pores. Two ILs, triethylsulfonium bis(trifluoromethylsulfonyl) imide [Set3][TFSI] and 1-butyl-1-methylpiperidinium bis(trifluoromethylsulfonyl)imide [C4C1Pip][TFSI], as well as their equimolar mixture [Set3/C4C1Pip], were used to obtain ionogel fibers. The developed...
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Mercury content in beetroot and beetroot-based dietary supplements
PublicationTotal mercury (THg) concentrations in fifty-four beetroot-based DSs and seven lots of conventional and organic beetroots (divided into unpeeled, peeled, and skins) were determined by direct thermal decomposition-gold amalgamation cold vapour atomic absorption spectrometry. The analytical procedure was optimised and validated. The recovery (%) for Hg was 101.9 and 92.73 in BCR-463 and DOLT 4, respectively. The intermediate precision...
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Application of a commercially available derivatization instrument and commonly used reagents to HPLC on-line determination of antioxidants
PublicationThis study demonstrates the potential of a commercially available derivatization instrument coupled with HPLC for separation and on-line determination of antioxidants detected with widely used screening reagents - DPPH (2,2-diphenyl-1-picrylhydrazyl), ABTS (2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) or FCR (Folin-Ciocalteu's phenol reagent ). As the result of optimization, key parameters of the analytical procedure,...
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Analysis of bisphenols and their derivatives in infant and toddler ready-to-feed milk and powdered milk by LC MS/MS
PublicationReady-to-feed milk and powdered milk packed in different types of packaging lined with resin are chosen as the primary or complementary diet for infants and toddlers. An HPLC–MS/MS method was established and validated for the determination of nineteen bisphenols and their derivatives in such samples. The recoveries were from 31% to 120%, while the values of limit of detection and quantification were in the range of 0.24–0.40 and...
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Advantageous conditions of saccharification of lignocellulosic biomass for biofuels generation via fermentation processes
PublicationProcessing of lignocellulosic biomass includes four major unit operations: pre-treatment, hydrolysis, fermentation and product purifcation prior to biofuel generation via anaerobic digestion. The microorganisms involved in the fermentation metabolize only simple molecules, i.e., monosugars which can be obtained by carrying out the degradation of complex polymers, the main component of lignocellulosic biomass. The object of this...
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Thermodynamic study of binary mixtures of 2-propanol with ionic liquids, 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-hexyl-3-methylimidazolium trifluoromethanesulfonate and triethylhexylammonium bis(trifluoromethylsulfonyl)imide
PublicationIn this work, densities, speeds of sound, refractive indices and viscosities of three binary mixtures containing the ionic liquids 1-hexyl-3-methylimidazolium bis(trifluoromethyl-sulfonyl)imide, 1-hexyl-3-methylimidazolium trifluoromethanesulfonate and triethylhexyl-ammonium bis(trifluoromethylsulfonyl)imide, mixed with 2-propanol at wide temperature and composition ranges at atmospheric pressure have been measured. From these...
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RP-HPLC WITH DETECTION BY MEANS OF ESI-MS AND UV FOR IDENTIFICATION OF CHROMATOGRAPHIC PEAKS OF SOME HYDROXY DERIVATIVES OF EPOXY RESIN
PublicationThe composition of products synthesized on the basis of ED-24 epoxy resin has been studied using a reversed phase high-performance liquid chromatography followed by an electrospray ionization mass spectrometry (RP-HPLC/ESI-MS). The synthesized products contain free hydroxy groups and such groups, as epoxy, peroxy, carboxy or acrylate.
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Multidisciplinary approach to the assessment of historic structures based on the case of a masonry bridge in Galicia (Spain)
PublicationThe paper presents a general method to evaluate a masonry structure with a complex geometry and unknown material properties. This multidisciplinary approach integrates close range digital photogrammetry,ground probing radar (GPR) and finite elements analysis (FEM) to analyse a masonry bridge. The resulting information from photogrammetry and radar is applied to define a 3D model, which is then used to simulate the behaviour of...
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Solvation of alkaline earth metal ions in N,N-dimethylformamide and N,N-dimethylacetamide – A volumetric and acoustic study
PublicationDensities and sound velocities at temperatures (298.15, 303.15, 308.15, 313.15 and 318.15) K of magnesium(II), calcium(II) and strontium(II) rifluoromethanesulfonates (triflates), as well as barium(II) perchloratein N,N-dimethylformamide (dmf) and N,N-dimethylacetamide (dma) have been measured over the composition range studied. From these results, apparent molar volumes and apparent molar isentropic compressibilities at infinite...
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Limiting Partial Molar Volumes of Tetra-n-Alkylammonium Perchlorates in N,N-dimethylacetamide, Triethylphosphate and Dimethyl Sulfoxide at 298.15 K
PublicationThe densities of tetraalkylammonium perchlorates R4NClO4(R = methyl, or ethyl, or propyl, or butyl) and ammonium perchlorate solutions in N, N - dimethylacetamide, dimethyl sulfoxide, and triethylphosphate have been measured over the whole composition range atT = 298.15 K. From these densities, apparent and limiting partial molar volumes of the electrolytes and ions...
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Apparent molar volumes and compressibilities of alkaline earth metal ions in methanol and dimethylsulfoxide
PublicationTemperature dependencies of density of magnesium (II), calcium (II), strontium (II), barium (II) perchlorates as well as beryllium (II), and sodium trifluoromethanesulfonates in methanol and dimethylsulfoxide have been determined over the composition range studied. From density data the apparent molar volumes and partial molar volumes of the salts at infinite dilution as well as the expansibilities have been evaluated. The apparent...
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Apparent molar volumes and compressibilities of selected electrolytes in dimethylsulfoxide
PublicationDensities at T = (293.15, 298.15, 303.15, 313.15, 323.15, and 333.15) K and sound velocities at T = 298.15 K of tetraphenylphosphonium bromide, sodium tetraphenylborate, sodium bromide, and sodium perchlorate in dimethylsulfoxide have been measured over the composition range from (0 to 0.3) mol kg1. From these data, apparent molar volumes and apparent molar isentropic compressibilitiesat infinite dilution as well as the expansibilities...
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Analysis of odour interactions in model gas mixtures using electronic nose and fuzzy logic
PublicationMeasurement and monitoring of air quality in terms of odour nuisance is an important problem. Although the source of these nuisances is different (e.g. wastewater treatment plants, municipal landfills), their common feature is that they are a complex mixture of odorants with different odour thresholds. An additional problem is occurrence of the odour interactions between mixture components. From a practical point of view, it would...
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Green sample preparation techniques for chromatographic determination of small organic compounds
PublicationAccurate monitoring of the state of the environment requires the introduction of additional isolation and/or preconcentration step prior to the chromatographic determination. In this work the information about novel methodological and instrumental solutions in relation to different variants of microextraction techniques are presented. Attention is focused on analytical procedure and suitable analytical tools for extraction of the...
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Optical investigations of electrochemical processes using a long-period fiber grating functionalized by indium tin oxide
Publicationhe growing needs for fast and reliable sensing devices stimulate development of new technological solutions. In this work a new multi-domain sensing method is demonstrated where optical sensing device has been applied to enhance amount of data received during electrochemical analysis. Thin, optically transparent, high-refractive-index, and electrically conductive indium tin oxide (ITO) film was deposited using magnetron sputtering...
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Synchrotron radiation photoemission spectroscopy of the oxygen modified CrCl3 surface
PublicationWe investigate the experimentally challenging CrCl3 surface by photon energy dependent photoemission (PE). The core and valence electrons after cleavage of a single crystal, either in a ultrahigh vacuum (UHV) or in air, are studied by keeping the samples at 150 1C, aiming at confirming the atomic composition with respect to the expected bulk atomic structure. A common spectroscopic denominator revealed by data is the presence of...
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Structure of solvation water around the active and inactive regions of a type III antifreeze protein and its mutants of lowered activity
PublicationWater molecules from the solvation shell of the ice-binding surface are considered important for the antifreeze proteins to perform their function properly. Herein, we discuss the problem whether the extent of changes of the mean properties of solvation water can be connected with the antifreeze activity of the protein. To this aim, the structure of solvation water of a type III antifreeze protein from Macrozoarces americanus (eel...
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Chemical identification of rubber fender sample and hardness and density measurements
PublicationScope of testing: Chemical identification of rubber fender sample and hardness and density measurements. - Raport z badań zleconych - Numer umowy: 031178
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Chemical Quality of Bottled Waters: A Review
PublicationBottled water has become very popular for quenching thirst and as a dietary (mineral) supplement. Theplethora of natural mineral waters precludes any unequivocal system of classification, which makes it difficult for theconsumer to choose a water with properties that suits him/her exactly. The ever-increasing popularity of bottled watersmeans that it is of the utmost importance to determine not only their mineral content, but above...