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Search results for: CHIRAL CHROMATOGRAPHY
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Modern approach for determination of lactulose, mannitol and sucrose in human urine using HPLC-MS/MS for the studies of intestinal and upper digestive tract permeability
PublicationA new analytical procedure was described for the simultaneous determination of lactulose, mannitol and sucrose in urine, in which HILIC chromatography and tandem mass spectrometry detection are used. Sugars are orally administered for the estimation of intestinal permeability in children digestive tract. Samples were purified by dispersive solid phase extraction (d-SPE) using Amberlite MB150 resin. Raffinose was selected as an...
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Spin and Orbital Effects on Asymmetric Exchange Interaction in Polar Magnets: M(IO3)2 (M = Cu and Mn)
PublicationMagnetic polar materials feature an astonishing range of physical properties, such as magnetoelectric coupling, chiral spin textures, and related new spin topology physics. This is primarily attributable to their lack of space inversion symmetry in conjunction with unpaired electrons, potentially facilitating an asymmetric Dzyaloshinskii–Moriya (DM) exchange interaction supported by spin–orbital and electron–lattice coupling. However,...
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China’s international trade and global value chains under One-Belt One-Road initiative
PublicationResearch background: After China acceded to the WTO in 2001, its foreign trade has expanded rapidly to be the largest share in the world. However, China's economic development changing from high-speed growth to medium high-speed growth in recent years. At the same time, the increase in labour cost and overcapacity also hinder China’s international trade. In order to solve these challenges and strengthening ties...
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Synthesis and characterization of modified silica gel as an intermediate in the generation of gaseous standard mixtures
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Determination of non-steroidal anti-inflammatory drugs in natural waters using off-line and on-line SPE followed by LC coupled with DAD-MS
PublicationOpisano dwie metody pozwalające na jednoczesne oznaczanie zawartości niesterydowych leków przeciwzapalnych (difluisal, diklofenak, naproksen, tolmetin, fenoprofen, ibuprofen) w próbkach wodnych. Próbki przygotowywano do analizy z użyciem techniki ekstrakcji do fazy stałej (off-line i on-line). Natomiast oznaczeń końcowych dokonano z użyciem LC-DAD-MS. Sprawdzono kilka różnych kolumienek ekstrakcyjnych i wybrano RP-18 jako najlepsze...
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Paraffin-Embedded Tissue as a Novel Matrix in Metabolomics Study: Optimization of Metabolite Extraction Method
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Comparison of Headspace-Single Drop Microextraction and Dispersive Liquid–Liquid Microextraction for Determination of Benzene in Juice Drinks Containing Vitamin C
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Comparison of Air-Assisted, Vortex-Assisted and Ultrasound-Assisted Dispersive Liquid–Liquid Microextraction for the Determination of BTEX Compounds in Water Samples Prior to GC-FID Analysis
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Static headspace sampling and solid-phase microextraction for assessment of edible oils stability
PublicationStatyczna analiza fazy nadpowierzchniowej i mikroekstrakcja do fazy stacjonarnej z fazy nadpowierzchniowej zostały zastosowane do oznaczenia niskocząsteczkowych aldehydów - markerów procesu utleniania olejów roślinnych. Zoptymalizowano parametry izolacji i ekstrakcji analitów dla obu technik. Wyznaczono granice oznaczalności i wykrywalności oraz powtarzalność dla badanych związków. Obie metody zastosowano w analizie próbek olejów...
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Preparation and evaluation of 1,3-alternate 25,27-bis[p-nitrobenzyloxy]-26,28-bis[3-propyloxy]-calix[4]arene-bonded silica gel stationary phase for LC
PublicationPrzeprowadzono syntezę nowej fazy stacjonarnej na bazie sililowej pochodnej 25,27-bis[p-nitrobenzyloksy]-26,28-bis-[3-propyloksy]kaliks[4]arenu zablokowanego w konformacji 1,3-naprzemianległej. Zbadano selektywność i sprawność fazy w stosunku do szeregu klas związków organicznych techniką wysokosprawnej chromatografii cieczowej.
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Possibilities of Production of New Reference Material ? Preparation of Gaseous Standard Mixtures Using Thermal Decomposition of Immobilized Compounds ? the Effect of Selected Parameters on the Amount of Released Analyte
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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...
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Abuse or contamination? Ratio determination of clenbuterol enantiomers to distinguish between doping use and meat contamination
PublicationClenbuterol has been detected in urine of several athletes during routine doping control in the past years. Athletes claimed that the clenbuterol was ingested by eating contaminated meat. Providing analytical prove for this claim is difficult. clenbuterol consists of two enantiomers, R(-) and S(+)-clenbuterol. Currently available human and veterinary preparations were found to consist of a racemic mixture of both enantiomers. When...
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The impact of China’s One-Belt One-Road initiative on international trade and global value chains
PublicationThis study examines the potential effects of China’s ‘One-Belt One-Road’initiative (OBOR) on trade flows and global value chain (GVC) connections.The empirical analysis is based on the augmented trade gravity model, which comprises 186 economies and 199 of their partners from 2000 to 2018. We also estimate the gravity model for involvement in GVC (domestic value added in intermediate exports, foreign value added in exports, and...
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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.
PublicationOpisano 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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New procedure of silica gel surface modification. Preparation of gaseousstandard mixtures for calibration purposes.
PublicationPrzedstawiono 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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Coacervative extraction as a green technique for sample preparation for the analysis of organic compounds
PublicationOne 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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CE-UV method for the determination of catecholamine metabolites from baby pee-covered diapers
PublicationA method has been developed for the analysis of vanillylmandelic acid, homovanillic acid, and 5-hydroxyindoleacetic acid from baby urine as biomarkers of neuroblastoma in infants. Disposable diapers were employed as sampling devices in order to guarantee a low invasiveness during this step. The proposed method consists on a simple extraction step with water from the used diaper followed by the measurement using capillary electrophoresis...
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Separation of C6 hydrocarbons on sodium dithionite reduced graphene oxide aerogels
PublicationThe ability of reduced graphene oxide aerogels (rGOAs) for challenging gas-phase separation was investigated with hexane isomers and benzene (C6 hydrocarbons) using inverse gas chromatography (IGC). For the first, rGOAs were synthesized with sodium dithionite (DTN) as a reductant. Experiments revealed that the most optimal DTN to graphene oxide mass ratio was 2:1, resulting in the highest specific surface area of 432.3 m2 g−1 and...
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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
PublicationPrzedstawiono 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
PublicationOpisano 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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Using different types of capillary columns as denudation traps: a comparision of sorption properties
PublicationOpisano 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
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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Three-step stacking of cationic analytes by field-enhanced sample injection, sweeping, and micelle to solvent stacking in capillary electrophoresis
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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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Characterization of 1,3-alternate calix[4]arene-silica bonded stationary phases and their comparison to selected commercial columns by using principal component analysis
PublicationTwelve 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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Open tubular trapping - present and future prospects
PublicationOtwarte 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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New matrix-free reference materials of volatile compounds - application of glass fibres as support materials for surface compounds
PublicationTechnika 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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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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Development and validation of UHPLC method for the determination of cyclosporine A in biological samples
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Multivariate assessment of anticancer oleanane triterpenoids lipophilicity
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Application of multicriteria decision analysis in solvent type optimization for chlorophenols determination with a dispersive liquid–liquid microextraction
PublicationThis 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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Modeling of small molecule's affinity to phospholipids using IAM-HPLC and QSRR approach enhanced by similarity-based machine algorithms
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Multicriteria decision analysis in ranking of analytical procedures for aldrin determination in water
PublicationThe 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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Recent developments and future trends in solid phase microextraction techniques towards green analytical chemistry
PublicationSolid 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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A fully validated HPLC–UV method for determination of sulthiame in human serum/plasma samples
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Three-step stacking by field-enhanced sample injection, sweeping, and micelle to solvent stacking in capillary electrophoresis: Anionic analytes
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Implementation of multicriteria decision analysis in design of experiment for dispersive liquid-liquid microextraction optimization for chlorophenols determination
PublicationA 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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Hydrophobic deep eutectic solvents as “green” extraction media for polycyclic aromatic hydrocarbons in aqueous samples
PublicationThe paper presents novel nonionic and hydrophobic deep eutectic solvents which were synthesized from natural compounds, i.e., thymol, ±camphor, decanoic and 10-undecylenic acids. Fundamental physicochemical properties of the synthesized deep eutectic solvents were determined, followed by their application as extractants in ultrasound-assisted dispersive liquid-liquid microextraction to isolate and enrich polycyclic aromatic hydrocarbons...
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Determination of polybrominated diphenyl ethers (PBDEs) in dust samples collected in air conditioning filters of different usage – method development
PublicationThis 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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Determination of thiocyanate as a biomarker of tobacco smoke constituents in selected biological materials of human origin
Publicationn 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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A magnetic imprinted polymer nano-adsorbent with embedded quantum dots and mesoporous carbon for the microextraction of triazine herbicides
PublicationA magnetic molecularly imprinted polymer (MMIP) adsorbent incorporating amino-functionalized magnetite nanoparticles, nitrogen-doped graphene quantum dots and mesoporous carbon (MIP@MPC@NGQDs@ Fe3O4–NH2) was fabricated to extract triazine herbicides from fruit juice. The embedded magnetite nanoparticles simplified the isolation of the adsorbent from the sample solution. The N-GQDs and MPC enhanced adsorption by affinity binding...
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Sample preparation procedure for the determination of polycyclic aromatic hydrocarbons in petroleum vacuum residue and bitumen
PublicationThis 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...