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Wyniki wyszukiwania dla: SUPERCRITICAL FLUID CHROMATOGRAPHY
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Chromatographic behaviour of ionic liquid cations in view of quantitative structure-retention relationship
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Determination of pyridine and adenine nucleotide metabolites in Bacillus subtilis cell extract by sweeping borate complexation capillary electrophoresis
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Analysis of carboxylic acid metabolites from the tricarboxylic acid cycle in Bacillus subtilis cell extract by capillary electrophoresis using an indirect photometric detection method
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Preparation and evaluation of solid-phase microextraction fibres based on functionalized latex nanoparticle coatings for trace analysis of inorganic anions
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Sputtered silicon solid phase microextraction fibers with a polydimethylsiloxane stationary phase with negligible carry-over and phase bleed
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The lipophilicity estimation of 5-arylidene derivatives of (2-thio)hydantoin with antimycobacterial activity
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Sample preparation for gas chromatographic determination of halogenated volatile organic compounds in environmental and biological samples
PublikacjaPodstawowym elementem przygotowania próbek środowiskowych i biologicznych do analizy jest etap izolacji i/lub wzbogacania polegający na przeniesieniu analitów z matrycy pierwotnej charakteryzującej się złożonym i często zmiennym składem (próbka oryginalna) do matrycy wtórnej z równoczesnym usunięciem substancji przeszkadzających (izolacja)i zwiększeniem stężenia analitów do poziomu powyżej granicy oznaczalności stosowanego przyrządu...
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New supervised alignment method as a preprocessing tool for chromatographic data in metabolomic studies
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Development and validation of UHPLC method for the determination of cyclosporine A in biological samples
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Thermodynamic vs. extrathermodynamic modeling of chromatographic retention
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A fully validated HPLC–UV method for determination of sulthiame in human serum/plasma samples
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Modeling of small molecule's affinity to phospholipids using IAM-HPLC and QSRR approach enhanced by similarity-based machine algorithms
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Application of the chromatographic retention index system for the estimation of the calibration constants of permeation passive samplers with polydimethylsiloxane membranes
PublikacjaThe paper presents the results of research on the calibration of permeation passive samplers equipped with polydimethylsiloxane (PDMS) membranes using the physico-chemical properties of the analytes. Strong correlations were found between the calibration constants of the samplers and the linear temperature-programmed retention indices of the analytes determined on columns coated with pure PDMS (r2 = 0.914). These correlations...
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New matrix-free reference materials of volatile compounds - application of glass fibres as support materials for surface compounds
PublikacjaTechnika termicznego rozkładu związków powierzchniowych, znana od ponad dziesięciu lat, ulega ciągłym udoskonaleniom w celu otrzymywania coraz szerszej gamy wzorców analitycznych występujących na coraz niższych poziomach stężeń. Początkowo w roli nośnika stosowano żel krzemionkowy, który w trakcie dalszych faz rozwoju tej techniki zastąpiono kolejno szkłem porowatym, a następnie włóknem szklanym. W ostatnim czasie uproszczono układ...
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Application of the chromatographic retention index system for theestimation of the calibration constants of permeation passivesamplers with polydimethylsiloxane membranes
PublikacjaW pracy przedstawiono wyniki badań z zastosowaniem pasywnych dozymetrów typu permeacyjnego, wyposażonych w membrany wykonane z PDMS. Badania dotyczyły oszacowania wartości stałych kalibracyjnych dozymetrów przy wykorzystaniu systemu indeksów retencji, wyznaczanych chromatograficznie, w warunkach liniowego narostu temperatury pracy kolumny (LTPRI). Znaleziono korelację pomiędzy wartościami stałych kalibracyjnych próbników typu pasywnego,...
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Using different types of capillary columns as denudation traps: a comparision of sorption properties
PublikacjaOpisano badania odcinków kapilarnych kolumn chromatograficznych (WCOT, SCOT,PLOT) jako pułapek denudacyjnych do ilościowego zatrzymywania śladowych ilości lotnych związków organicznych ze strumienia powietrza. W trakcie badań modelowych (z wykorzystaniem gazowych mieszanin wzorcowych) określono wartości współczynników podziału benzenu, toluenu, etylobenzenu, o-ksylenu i chlorobenzenu (Kfs). Stwierdzono, że grubość filmu fazy stacjonarnej...
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Evaluation of headspace solid-phase microextraction for the analysis of volatile carbonyl compounds in spirits and alcoholic beverages
PublikacjaOpracowano 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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Solid phase extraction clean up of soil and sediment extracts for the determination of various types of pollutants in a single run.
PublikacjaOpisano nową procedurę oczyszczania ekstraktów rozpuszczalnikowych (uzyskanych w trakcie obróbki próbek gleby i osadów dennych) z wykorzystaniem techniki ekstrakcji do fazy stałej. Oryginalność podejścia polega na znalezieniu takiej kombinacji sorbentów, że uzyskuje się ekstrakt przygotowany do analizy chromatograficznej na zawartość różnych typów zanieczyszczeń (polichlorowane bifenyle, wielopierścieniowe węglowodory aromatyczne,...
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Matrix effects and recovery calculations in analyses of pharmaceuticals based on the determination of β-blockers and β-agonists in environmental samples
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New procedure of silica gel surface modification
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Use of porous glass and silica gel as support media of a surface compound for generation of analytes in gaseous standard mixtures. New method for the determination of the amount of analyte generated
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Generation of standard gaseous mixtures by thermal decomposition of surface compounds
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New procedure of silica gel surface modification. Preparation of gaseousstandard mixtures for calibration purposes.
PublikacjaPrzedstawiono nową procedurę modyfikacji powierzchni żelu krzemionkowego z wykorzystaniem trimetyloaminy jako odczynnika. Próbki chemiczne modyfikowanego nośnika zostały wykorzystane do sporządzenia gazowych mieszanin wzorcowych (chlorek metylu jako składnik mierzony) techniką termicznego rozkładu związków powierzchniowych. Głównym celem badań było sprawdzenia przydatności nowej procedury modyfikacji powierzchni żelu do...
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Determination of the amount of wash amines and ammonium ion in desulfurization products of process gases and results of related studies
PublikacjaPrzedstawiono metodę oznaczania tzw. amin myjących i ich produktów degradacji, włączając jon amonowy w wodach procesowych i ściekach wytwarzanych podczas odsiarczania gazów. W procesach rafinacji ropy naftowej zastosowano jonowymienną chromatografię cieczową z detektorem refraktometrycznym oraz tanią kationowymienną kolumnę HPLC. Otrzymane wyniki oznaczeń porównano z wynikami uzyskanymi przez miareczkowanie potencjometryczne....
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Miniaturised analytical procedure of determining polycyclic aromatic hydrocarbons and polychlorinated biphenyls in bottom sediments
PublikacjaOpisano metodę oznaczania bardzo niskich stężeń polichlorowanych bifenyli w obecności wysokich zawartości wielopierścieniowych węglowodorów aromatycznych. Analizie techniką GC-MS poddawany jest ekstrakt z 1 g próbki osadu. Jako standardy wewnętrzne zastosowano Naftalen-d8, benzo[a]antracen-d12 i PCB 209. Średni odzysk standardów przedstawiał się następująco: 65, 55 i 60% odpowiednio. Do izolacji frakcji PCB stosowano niekomercyjne...
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Estimating uncertainty in analytical procedures based on chromatographic techniques
PublikacjaTechniki chromatograficzne są bardzo często wykorzystywane w procedurach analitycznych na etapie rozdzielania i oznaczania oraz identyfikacji szerokiego spektrum analitów występujących w próbkach charakteryzujących się złożonym a niekiedy także zmiennym matryce. Bardzo często są jednak sytuacje, że przy oszacowywaniu niepewności wyników oznaczeń końcowych pomija się niepewności związane z procesem chromatograficznym. W efekcie...
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Recent developments and future trends in solid phase microextraction techniques towards green analytical chemistry
PublikacjaSolid phase microextraction find increasing applications in the sample preparation step before chromatographic determination of analytes in samples with a complex composition. These techniques allow for integrating several operations, such as sample collection, extraction, analyte enrichment above the detection limit of a given measuring instrument and the isolation of analytes from sample matrix. In this work the information about...
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Multicriteria decision analysis in ranking of analytical procedures for aldrin determination in water
PublikacjaThe study presents the possibility of multi-criteria decision analysis (MCDA) application when choosing analytical procedures with low environmental impact. A type of MCDA, Preference Ranking Organization Method for Enrichment Evaluations (PROMETHEE), was chosen as versatile tool that meets all the analytical chemists – decision makers requirements. Twenty five analytical procedures for aldrin determination in water samples (as...
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Coacervative extraction as a green technique for sample preparation for the analysis of organic compounds
PublikacjaOne of the present trends in analytical chemistry is miniaturization, which is one of the methods of green analytical chemistry application. A particular emphasis is placed on the elimination of the use of large amounts of organic solvents which are toxic and harmful to the environment, maintaining high efficiency of the extraction process, high recovery values and low values of quantification (LOQ) and detection (LOD) limits....
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Multivariate assessment of anticancer oleanane triterpenoids lipophilicity
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Open tubular trapping - present and future prospects
PublikacjaOtwarte pułapki kapilarne posiadają pewne unikalne właściwości, które ułatwiają ich zastosowanie zarówno w analizie próbek gazowych jak i wodnych - na przykład niskie opory przepływu umożliwiają ich bezpośrednie połączenie z większością technik rozdzielania chromatograficznego. W pracy opisano etapu rozwoju OTT na przestrzeni ostatnich kilkunastu lat, ze szczególnym uwzględnieniem aspektów technologii ich wytwarzania oraz sposobów...
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Chromatographic lipophilicity determination using large volume injections of the solvents non-miscible with the mobile phase
PublikacjaA new perspective in the lipophilicity evaluation through RP-HPLC is permitted by analysis of the retentionfactor (k) obtained by injecting large volumes of test samples prepared in solvents immiscible withmobile phase. The experiment is carried out on representative groups of compounds with increasedtoxicity (mycotoxins and alkaloids) and amines with important biological activity (naturally occurringmonoamine compounds and related...
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Determination of thiocyanate as a biomarker of tobacco smoke constituents in selected biological materials of human origin
Publikacjan order to protect human health, it is necessary to biomonitor toxic substances originating from tobacco smoke in biological materials sampled from persons with different exposures to tobacco smoke constituents. Thiocyanate anion is a biomarker of exposure to tobacco smoke components which is characterized by a relatively long half‐life in the human body, i.e. 6 days. In this work, we present the results of thiocyanate determinations...
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Determination of polybrominated diphenyl ethers (PBDEs) in dust samples collected in air conditioning filters of different usage – method development
PublikacjaThis study presents the results of studies aimed at the development of an analytical procedure for separation, identification, and determination of PBDEs compounds in dust samples collected from automotive cabin air filters and samples collected from filters installed as part of the air purification system in academic facilities. Ultrasound-assisted dispersive solid phase extraction (UA-dSPE) was found to perform better in terms...
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Application of multicriteria decision analysis in solvent type optimization for chlorophenols determination with a dispersive liquid–liquid microextraction
PublikacjaThis study presents a novel support tool for the optimization and development of analytical methods. The tool is based on multi-criteria decision analysis (MCDA), namely the Technique for Order of Preference by Similarity to the Ideal Solution (TOPSIS), that allows users to rank possible solutions according to their requirements. In this study, we performed rankings of pairs of eight extraction and three dispersive solvents used...
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Characterization of 1,3-alternate calix[4]arene-silica bonded stationary phases and their comparison to selected commercial columns by using principal component analysis
PublikacjaTwelve calix[4]arene stationary phases in 1,3-alternate conformation, synthesized in the authors laboratory, were characterized in terms of their surface coverage, hydrophobic selectivity, aromatic selectivity, shape selectivity, hydrogen bonding capacity and ion-exchange capacity. The set of tests commonly used for evaluation of commercially available stationary phases was applied to assess fundamental chromatographic properties...
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Implementation of multicriteria decision analysis in design of experiment for dispersive liquid-liquid microextraction optimization for chlorophenols determination
PublikacjaA novel and efficient approach to optimization of extraction step prior the chromatographic determination of nine chlorinated phenols is described. It is based on the combination of design of experiments and multicriteria decision analysis. Such an approach is used to optimize dispersive liquid-liquid microextraction procedure for the determination of 9 chlorophenols in water samples. Three parameters are optimized – sample volume,...
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Sample preparation procedure using extraction and derivatization of carboxylic acids from aqueous samples by means of deep eutectic solvents for gas chromatographic-mass spectrometric analysis
PublikacjaThe paper presents a new procedure for the determination of organic acids in a complex aqueous matrixusing ultrasound-assisted dispersive liquid–liquid microextraction followed by injection port derivati-zation and GC–MS analysis. A deep eutectic solvent (choline chloride: 4-methylphenol in a 1:2 mol ratio)was used both as an extracting solvent and as a derivatizing agent to yield ion pairs which were next con-verted to methyl...
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Activation Energy and Inclination Magnetic Dipole Influences on Carreau Nanofluid Flowing via Cylindrical Channel with an Infinite Shearing Rate
PublikacjaThe infinite shear viscosity model of Carreau fluid characterizes the attitude of fluid flow at a very high/very low shear rate. This model has the capacity for interpretation of fluid at both extreme levels, and an inclined magnetic dipole in fluid mechanics has its valuable applications such as magnetic drug engineering, cold treatments to destroy tumors, drug targeting, bio preservation, cryosurgery, astrophysics, reaction kinetics,...
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Sample preparation procedure for the determination of polycyclic aromatic hydrocarbons in petroleum vacuum residue and bitumen
PublikacjaThis paper describes a novel method of samplepreparation for the determination of trace concentrations ofpolycyclic aromatic hydrocarbons (PAHs) in high-boilingpetroleum products. Limits of quantitation of the investigatedPAHs in materials of this type range from tens ofnanograms per kilogram to <20 μg/kg. The studies revealedthat in order to separate most of interferences from theanalytes without a significant loss of PAHs, it...
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Turmeric nanofiber-encapsulated natural product formulation act as a phytogenic feed additive—A study in broilers on growth performance, biochemical indices of blood, and E. coli in cecum
PublikacjaA phytogenic feed additive (PFA) formulation was prepared with bioactive molecules—curcuminoids, gingerol, and carvacrol by encapsulating in nanofiber isolated from turmeric spent (turmeric nanofiber, TNF). This formulation was completely characterized by scanning electron microscope, ultra performance liquid chromatography, and gas chromatography and evaluated for its efficacy. PFA-encapsulated TNF (PFA@TNF) considerably increased...
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Experimental investigation of forced convection of water/EGAl2O3 nanofluids inside horizontal tube
PublikacjaIn this paper, forced convection of water/EG-Al2O3 nanofluids inside horizontal stainless steel tube is studied experimentally. As base fluid served water/EG mixture of two ratios (60:50 and 50:50). Nanoparticle mass concentrations was 0.1% or and 1%. Transition and turbulent flow regimes were tested. Average heat transfer coefficient and pressure drop values were determined for nanofluids and compared to base fluids. Deterioration...
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Real-Time Monnitoring of Vegetable Oils' Thermal Degradation Using Proton Transfer Reaction Mass Spectrometry
PublikacjaThe volatile aldehydes, which are generated during frying, can be harmful to human health, therefore the concentration of these compounds in frying fumes should be monitored. In addition, aldehydes are markers of oils’ quality, and so it is possible to determine shelf-life or suitability for frying of these oils. Commonly, in order to determine aldehydes concentration gas chromatography is performed, however it does not allow for...
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Theoretical Organic Rankine Cycle efficiency depending on different thermodynamic work variables.
PublikacjaOne of promising technologies of utilizing low- temperature waste heat is through ORC (Organic Rankine Cycle) system implementation. A primary objective in designing in-stallations based on such systems is to maximize the installation's work efficiency. On the other hand, ecological factors are commonly considered a natural barrier in introducing new, often very expensive technologies. Ecological effect of a potential modernization...
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WSPÓŁPRACA BLOKU GAZOWO-PAROWEGO Z OBIEGIEM ORC = Combinded power plant in cooperation with ORC
PublikacjaIn the paper presented is the idea of a combined gas and steam power plant cooperation with a low temperature organic Rankine cycle ORC unit. Considerations presented in the paper are accomplished for the Gorzów CHP. The intention of present analysis is heat recovery of low temperature energy and its further use in ORC cycle in order to produce electricity, without increase in fuel consumption. Waste energy is recovered from the...
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Gas boiler as a heat source for the domestic micro-CHP
PublikacjaIn the presented analysis a commercially available domestic gas boiler as a heat source for domestic ORC is considered. The applicability of the gas boiler (De Dietrich with thermal power 25 kW) coupled with the laboratory prototype micro ORC setup has experimentally studied. The main aim of the study is to determine the working fluid temperature, attainable heat rates and efficiencies of the whole system. Preliminary investigations...
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Subcritical bifurcation of free elastic shell of biological cluster
PublikacjaIn this paper we will investigate symmetry-breaking bifurcation of equilibrium forms of biological cluster. A biological cluster is a two-dimensional analogue of a gas balloon. The cluster boundary is connected with its kernel by elastic links. The inside part is filled with compressed gas or fluid. Equilibrium forms of biological cluster can be found as solutions of a certain second order ordinary functional-differential equation...
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Gas boiler as a heat source for the domestic micro-CHP
PublikacjaThis analysis considers a commercially available domestic gas boiler as a heat source for a domestic organic Rankine cycle system. An experimental study was made into the applicability of the gas boiler (De Dietrich with thermal power 25 kW) coupled with the laboratory prototype micro ORC setup. The main aim of the study is to determine the working fluid temperature, attainable heat rates and effciencies of the whole system. Preliminary...
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Influence of local bush wear on water lubricated sliding bearing load carrying capacity
PublikacjaOne of main problems concerning water-lubricated bearings is their durability. There are known cases of bearings with life time measured in decades, and some, whose refurbishment was necessary just days after start-up. Obtaining stable fluid film friction plays key role in the durability of these bearings. Unfortunately, their load-carrying capacity is limited due to water's low-viscosity. The conducted experimental...
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ENHANCED MASTER CYCLE - SIGNIFICANT IMPROVEMENT OF STEAM RANKINE CYCLE
PublikacjaThe present paper focuses on an enhancement of the Master Cycle. In the first part, the paper presents a classical Master Cycle which is a modification of the double reheat Rankine cycle. This modification allows to slightly increase efficiency, resolves problems caused by superheated steam on bleeds and decreases mass flow rate of steam directed to reheat. These improvements include the implementation of a tuning turbine from...