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Search results for: REVERSE PHASE COLUMN
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Influence of dispersed phase content on the mechanical properties of electroless nanocomposite Ni-P/Si3N4 and hybrid Ni-P/Si3N4/graphite layers deposited on the AW-7075 alloy.
PublicationThe article presents the results of mechanical testing of Ni-P/Si3N4 nanocomposite and hybrid Ni-P/Si3N4/graphite coatings deposited on AW-7075 aluminum alloy using the chemical reduction method. In terms of mechanical testing, microhardness was measured, and surface roughness and adhesion of the coatings to the aluminum substrate were determined using the “scratch test” method. The surface morphology of the deposited layers was...
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Development of a vortex-assisted switchable-hydrophilicity solvent-based liquid phase microextraction for fast and reliable extraction of Zn (II), Fe (II), Pb (II), and Cd (II) from various baby food products
PublicationThis manuscript describes the development of a novel liquid phase microextraction (LPME) method for the extraction and determination of Zn (II), Fe (II), Pb (II), and Cd (II) in various infant/baby food and supplements products. The method is based on vortex-assisted extraction combined with a switchable-hydrophilicity solvent (SHS) sample preparation. The SHS, which undergoes reversible phase changes triggered by pH change, enables...
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Effect of Cr and Mn doping on ferroelectric and dielectric properties of Li1.72Na0.28Ge4O9 single crystals
PublicationLi1.72Na0.28Ge4O9 single crystals pure and slightly doped with chromium and manganese, obtained by Czochralski growth, were investigated for their ferroelectric and dielectric properties. The change in stoichometry of Li2− x Na x Ge4O9 (x = 0.28) crystals doped with Cr and Mn (0.1 mol.%) had an influence on the value of ferroelectric-to-paraelectric phase transition temperature, T c. The applied doping affects the T c value by...
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Ultrasound assisted dispersive solid phase microextraction using polystyrene-polyoleic acid graft copolymer for determination of Sb(III) in various bottled beverages by HGAAS
PublicationA new polyoleic acid-polystyrene (PoleS) block/graft copolymer was synthesized and applied as adsorbent for ultrasound assisted dispersive solid phase microextraction (UA-DSPME) of Sb(III) in different bottled beverages and analysis using hydride generation atomic absorption spectrometry (HGAAS). Adsorption capacity of the PoleS was 150 mg g−1. Several sample preparation parameters such as sorbent amount, solvent type, pH, sample...
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Green capsule phase microextraction employing hydrophobic monolithic sol-gel octadecyl siloxane platforms for the monitoring of organophosphorus pesticides in environmental water samples
PublicationIn this study, a novel, facile and green capsule phase microextraction (CPME) method is presented for the extraction and preconcentration of organophosphorus pesticides (i.e., chlorpyrifos, disulfoton, ethoprophos, fenchlorphos, prothiofos, and parathion-methyl) from environmental water samples. Monolithic sol-gel octadecyl siloxane (sol-gel C18) sorbent encapsulated within porous polypropylene capsules was synthesized, characterized,...
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Chromium‑based metal organic framework for pipette tip micro‑solid phase extraction: an effective approach for determination of methyl and propyl parabens in wastewater and shampoo samples
PublicationAbstract Background A chromium-based metal organic framework was synthesized and employed as an efficient sorbent for pipette tip micro-solid phase extraction and preconcentration of parabens from wastewater and shampoo samples up to sub-ppb level before their spectrophotometric analysis. Results Factors affecting preconcentration including volume and type of solvent, amount of sorbent, number of extraction, and volume and pH of...
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Comparison of classical and modern approach of determination of highly polar compounds by High Performance Liquid Chromatography coupled with Tandem Mass Spectrometry
PublicationAbstract: Sugars and sugar alcohols are known as highly polar compounds. Four analytes were taken into consideration for comparison of classical and modern approach of separation of highly polar substances. Mannitol was chosen as an example of simple sugar alcohol, sucrose and lactulose as examples of disaccharides and structural isomers, raffinose as an example of complex trisaccharide. Raffinose was also used as internal standard...
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Silica-Based Ionogels: Nanoconfined Ionic Liquid-Rich Fibers for Headspace Solid-Phase Microextraction Coupled with Gas Chromatography–Barrier Discharge Ionization Detection
PublicationIn this work, hybrid silica-based materials with immobilized ionic liquids (ILs) were prepared by sol–gel technology and evaluated as solid-phase microextraction (SPME) fiber coatings. High loadings of the IL 1-methyl-3-butylimidazolium bis(trifluoromethylsulfonyl)imide ([C4MIM][TFSI]) were confined within the hybrid network. Coatings composition and morphology were evaluated using scanning electron microscopy and energy dispersive...
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Design of three-phase three-level CIC T-source inverter with maximum boost control
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Polystyrene/polybutadiene blends: An analysis of the phase-inversion region and cophase continuity and a comparison with theoretical predictions
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Polystyrene/polybutadiene blends: An analysis of the phase-inversion region and cophase continuity and a comparison with theoretical predictions
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Safety and efficacy of lenabasum in a phase 2 randomized, placebo-controlled trial in adults with cystic fibrosis
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3-phase medium frequency transformer for a 100kW 1.2kV 20kHz Dual Active Bridge converter
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Early stages of condensation from the gaseous phase in a H2O-N2 system: a molecular dynamics study.
PublicationW pracy przedstawiono wyniki symulacji wczesnych etapów kondensacji z fazy gazowej w układzie xH2O (1-x)N2. Przeanalizowano całkowitą liczbę klastrów, średni rozmiar klastra i rozmiar klastra maksymalnego w funkcji czasu.
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Nieliniowy model matematyczny transformatora trójfazowego = Non-linear mathematical model of a three-phase transformer
PublicationPrzedstawiono model transformatora trójfazowego o rdzeniu trójkolumnowym, który zawiera układ rów-nań opisujących obwód magnetyczny oraz oddzielnie układ równań obwodu elektrycznego. Wydzielenie re-luktancji elementów rdzenia umożliwia uwzględnienie zmian względnej przenikalności magnetycznej w funkcji bieżącej wartości strumienia w rdzeniu. Re-luktancje odpowiadające strumieniom rozproszenia obliczono wg zasad klasycznych. Funkcję...
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Evaluation of headspace solid-phase microextraction for the analysis of volatile carbonyl compounds in spirits and alcoholic beverages
PublicationOpracowano metodę oznaczania C1-C6 związków karbonylowych w układzie GC-ECD w roztworach alkoholowych poprzez derywatyzację pentafluorobenzylohydroksy-aminą i mikroekstrakcję w fazie stacjonarnej z fazy nadpowierzchniowej. Zoptymalizowano warunki eksperymantalne: zawartość alkoholu, czas ekspozycji, temperaturę i sposób mieszania próbki. W metodzie tej najpierw przeprowadza się rozcieńczenie spirytusu lub napojów alkoholowych do...
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New type of repeated Si–C-podand catalysts for solid–liquid phase transfer reactions
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Synthesis of Novel Arginine Building Blocks with Increased Lipophilicity Compatible with Solid-Phase Peptide Synthesis
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Luminescence enhancement in nanocrystalline Eu2O3 nanorods – Microwave hydrothermal crystallization and thermal degradation of cubic phase
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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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The influence of type of dispersed phase on rolling contact fatigue of lubricating greases on mineral base oil
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Synthesis and structural properties of carbon/alumina composites: Practical application in solid phase extraction of explosives
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Custom FBGs inscription using modified phase mask method with precise micro- and nano-positioning
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Quasi-discrete modelling of PMSM phase currents in drives with low switching-to-fundamental frequency ratio
PublicationThis study proposes a new quasi-discrete approach to modelling the permanent magnet synchronous motor (PMSM). The quasi-discrete modelling reflects the impact of continuous rotor movement, which takes place during a control cycle, on the shape of motor current waveforms. This provides much improvement in current modelling accuracy under inverter low switching-to-fundamental frequency operation. The proposed approach may be used...
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Lipophilicity data for some preservatives estimated by reversed-phase liquid chromatography and different copmutation methods
PublicationW 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
PublicationDo 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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On the critical temperature discontinuity at the theoretical bcc-fcc phase transition in compressed selenium and tellurium superconductors
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Evaluation of the High-Pressure Gas Transmission Network Impact for Environmental - Construction Phase and Network Operation
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Phase Transitions and Structural Changes in DPPC Liposomes Induced by a 1-Carba-Alpha-Tocopherol Analogue
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Iron and other metal species as phase-composition controllers influencing the photocatalytic activity of TiO2 materials
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Phase behavior of π-conjugated polymer and non-fullerene acceptor (PTB7-Th:ITIC) solutions and blends
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Structure of the twist-bend nematic phase with respect to the orientational molecular order of the thioether-linked dimers
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Biaxial order and a rotation of the minor director in the nematic phase of an organo-siloxane tetrapode by the electric field
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Distortions in structures of the twist bend nematic phase of a bent-core liquid crystal by the electric field
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Determination of butyltin stabilizers in PVC using Liquid-Phase microextraction with electrothermal atomic absorption spectrometry
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Impedance spectroscopy of BaTiO3 cubes suspended in lossy liquids as a physical model of two-phase system
PublicationTechniki spektroskopii impedancyjnej zostały wykorzystane do analizy modelu fizycznego w układzie dwufazowym w celu wyznaczanie stałej dielektrycznej dielektryka umieszczonego w cieczy. Badania eksperymentalne przeprowadzono z użyciem BaTiO3 jako materiału dielektrycznego, który został przygotowany jako kostki o jednakowej wielkości 2x2x1 mm3.
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Application of sublation and two phase titration methods for analytical of surfactants in AFFF fire-fighting foams
PublicationCelem badań była próba opracowania odpowiedniej metody izolacji ze ścieków fluorowanych związków powierzchniowo czynnych FZPC do celów analitycznych, a także metody ich ilościowego oznaczania. W badaniach polegających na oznaczaniu stężenia FZPC w oparciu o miareczkowanie w układzie dwufazowym: woda/chloroform użyto Hyaminy 1622, jako titranta oraz błękitu metylenowego, jako wskaźnika. Kolejnym etapem badań była izolacja ZPC z...
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Solid phase microextraction combined with chromatography - a powerful tool for determination of warfare agents and related compounds
PublicationOpisano zastosowanie mikroekstrakcji do fazy stacjonarnej do izolacji wzbogacania środków bojowych i produktów ich degradacji w powietrzu, wodzie i glebie oraz próbkach bilogicznych. Na etapie oznaczeń końcowych stosuje się najczęściej chromatografię gazową. Anality można pobierać przez bezpośrednie zanurzenie włókna w próbce ciekłej i gazowej oraz w fazie nadpowierzchniowej. Stosując SPME-GC można osiągnąć niskie granice oznaczalności...
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Evaluation of Three Peptide Immobilization Techniques on a QCM Surface Related to Acetaldehyde Responses in the Gas Phase
PublicationThe quartz-crystal microbalance is a sensitive and universal tool for measuring concentrations of various gases in the air. Biochemical functionalization of the QCM electrode allows a label-free detection of specific molecular interactions with high sensitivity and specificity. In addition, it enables a real-time determination of its kinetic rates and affinity constants. This makes QCM a versatile bioanalytical screening tool for...
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Recycled Polyurethane as a Second Phase in Thermoset Blends and Its Effect on Thermal Degradation Kinetics Studies
PublicationA new approach is introduced in the modification of thermosetting polymer by using different amount of polyurethane of waste origin. The post consumer polyurethane foam coatings are degraded using glycolysis process and the recycled product is further converted into new polyurethane. The blending of recycled polyurethane with epoxy exhibits transparency and produces nanostructures. The effective interaction between two polymers...
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Possibilities and benefits of a new method of modifying conventional building materials with phase-change materials (PCMs)
PublicationThe paper presents a current study devoted to the optimization of the amount of PCM present within traditional building materials, utilized in this case in hollow-brick walls. Authors focus on proposing an alternative to typical direct addition of PCM to existing building materials: introducing two- and three-component mixtures, based on a porous PCM carrier, which in this case was construction aggregate. Preliminary studies of...
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Adsorption of 1,2-Dichlorobenzene from the Aqueous Phase onto Activated Carbons and Modified Carbon Nanotubes
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Understainding solid-phase microextraction: key factors influencing the extraction process and trends in improving the technique
PublicationAnalytical chemists are faced with the daunting challenges of accurately monitoring the state of the environment and the processes taking place in it and of determining an enormous range of analytes often present in trace and ultratrace amounts in sample matrixes with complex or variable compositions. Further challenges are presented by the need to introduce new methodologies into current analytical practice and equipment to comply...
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Experimental investigations of hydraulic jump created by a two-phase impin-ging jet on a solid surface
PublicationPrzedstawiono rezultaty badań eksperymentalnych powstawania uskoku hydraulicznego tworzonego przez dwufazową strugę uderzającą.
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Polystyrene/polybutadiene blends: an analysis of the phase inversion regionand cophase continuity and a comparison with theoretical predictions.
PublicationMieszaniny przygotowano przez mieszanie w stopie. Występowanie jednego lubobu polimerów w postaci fazy ciągłej stwierdzano przez badanie morfologii przy pomocy skaningowego mikroskopu elektronowego i przez rozpuszczanie jednego ze składników mieszaniny. Badania morfologii mieszanin wykazały, że polistyren występował w postaci globul przy jego zawartości do 30%. Przy zawartości od 40% do 60% obserwowano fazy ciągłe obu...
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Initial stage of (Bi-Pb)2Sr2Ca1Cu2Ox high Tc superconductor crystallisation from the amorphous phase.
PublicationWysokotemperaturowe nadprzewodniki bizmutowe 2201, 2212 i 2223 były wytwarzane metodą krystalizacji w fazie stałej. Zmiany struktury i mikrostruktury badano metodą dyfrakcji rentgenowskiej oraz skanningowej mikroskopii elektronowej. Zbadano kinetykę krystalizacji oraz przedyskutowano jej przebieg.
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Dispersive Micro‐Solid Phase Extraction of Selected Metals in Water and Food Samples Followed by ICP‐OES Analysis: Method Development, Analysis of Real Samples and Greenness Evaluation
PublicationMultiwalled carbon nanotubes (MWCNTs) are well-known adsorbents because of their high surface area, layered and hollow architecture, hydrophobicity, and multiple and easily accessible adsorption sites. In this study, MWCNTs were used for dispersive micro-solid-phase extraction of various metal chelates in environmental and food samples. Different parameters such as concentration of the chelating reagent, the sorbent dosage, the...
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Optimization of a Fabric Phase Sorptive Extraction protocol for the isolation of six bisphenols from juice pouches to be analysed by high performance liquid chromatography coupled with diode array detector
PublicationFabric Phase Sorptive Extraction (FPSE) combined with high pressure liquid chromatography using to diode array detection (HPLC-DAD) was applied for the simultaneous determination of bisphenols (BPA, BPB, BPC, BPE, BPF, BPS) in juice pouches. The FPSE procedure was optimized with regards to the critical parameters that affect the performance of the method including the selection of the FPSE membrane type and size, adsorption time,...
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Investigation of use of hydrophilic/hydrophobic NADESs for selective extraction of As(III) and Sb(III) ions in vegetable samples: Air assisted liquid phase microextraction and chemometric optimization
PublicationIn this paper, a green, cost-effective sample preparation method based on air assisted liquid phase microextraction (AA-LPME) was developed for the simultaneous extraction of As(III) and Sb(III) ions from vegetable samples using hydrophilic/hydrophobic natural deep eutectic solvents (NADESs). Central composite design was used for the optimization of extraction factors including NADES volume, extraction cycle, pH, and curcumin concentration....
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Application of Headspace Solid-phase Microextraction with Poly(1-vinyl-3- Hexylimidazolium Chloride) Polymeric Ionic Liquid Coating using GC - MS to Determine Volatile Fatty Acids in Dairy Wastewater
PublicationVolatile fatty acids were determined in this study using headspace solid-phase microextraction (HS-SPME) with a poly(1-vinyl-3-hexylimidazolium chloride) polymeric ionic liquid coated fiber followed by gas chromatography - mass spectrometry. Experimental parameters such as extraction time and temperature, sample volume as well as desorption time and temperature were optimized. Detection limits of the method were in the range of...