Selectivity in CE
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High surface-area, mesoporous CeO2, ZrO2, and Ce-Zr composite nanoparticles were developed using the hydrothermal template-assisted synthesis method. Samples were characterized using XRD, N2 physisorption, TEM, XPS, and FT-IR spectroscopic methods. The CO2 adsorption ability of the obtained materials was tested under dynamic and equilibrium conditions. A high CO2 adsorption capacity in CO2/N2 flow or CO2/N2/H2O was determined for all studied adsorbents depending on their composition flow. A higher CO2 adsorption was registered for Ce-Zr composite nanomaterials due to the presence of strong O2- base sites and enriched surface oxygen species. The role of the Ce/Zr ratio is the process of the formation of highly active and selective adsorption sites is discussed. The calculated heat of adsorption revealed the processes of chemisorption and physisorption. Experimental data could be appropriately described by the Yoon-Nelson kinetic model. The composites reused in five adsorption/desorption cycles showed a high stability with a slight decrease in CO2 adsorption capacities in dry flow and in the presence of water vapor.
- Klíčová slova
- CO2 capture, Ce-Zr composite nanoparticles, CeO2, ZrO2,
- Publikační typ
- časopisecké články MeSH
ABSTRACT: Quantum dots (QDs) are fluorescence nanoparticles (NPs) with unique optic properties which allow their use as probes in chemical, biological, immunological, and molecular imaging. QDs linked with target ligands such as peptides or small molecules can be used as tumor biomarkers. These particles are a promising tool for selective, fast, and sensitive tagging and imaging in medicine. In this study, an attempt was made to use QDs as a marker for human metallothionein (MT) isoforms 1 and 2. Four kinds of CdTe QDs of different sizes bioconjugated with MT were analyzed using the chip-CE technique. Based on the results, it can be concluded that MT is willing to interact with QDs, and the chip-CE technique enables the observation of their complexes. It was also observed that changes ranging roughly 6-7 kDa, a value corresponding to the MT monomer, depend on the hydrodynamic diameters of QDs; also, the MT sample without cadmium interacted stronger with QDs than MT saturated with cadmium. Results show that MT is willing to interact with smaller QDs (blue CdTe) rather than larger ones QDs (red CdTe). To our knowledge, chip-CE has not previously been applied in the study of CdTe QDs interaction with MT.
- Klíčová slova
- Bioconjugation, Biomarkers, Chip-CE, Health effects, Metallothionein, Quantum dots,
- Publikační typ
- časopisecké články MeSH
The family of deubiquitinases (DUBs) comprises ∼100 enzymes that cleave ubiquitin from substrate proteins and thereby regulate key aspects of human physiology. DUBs have recently emerged as disease-relevant and chemically tractable, although currently there are no approved DUB-targeting drugs and most preclinical small molecules are low-potency and/or multitargeted. We paired a novel capillary electrophoresis microchip containing an integrated, "on-chip" C18 bed (SPE-ZipChip) with a TMT version of our recently described PRM-LIVE acquisition scheme on a timsTOF Pro mass spectrometer to facilitate rapid activity-based protein profiling of DUB inhibitors. We demonstrate the ability of the SPE-ZipChip to improve proteome coverage of complex samples as well as the quantitation integrity of CE-PRM-LIVE for TMT labeled samples. These technologies provide a platform to accurately quantify competitive binding of covalent and reversible inhibitors in a multiplexed assay that spans 49 endogenous DUBs in less than 15 min.
- MeSH
- deubikvitinasy metabolismus MeSH
- elektroforéza kapilární MeSH
- elektroforéza mikročipová * MeSH
- lidé MeSH
- proteom MeSH
- ubikvitin * metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
- Názvy látek
- deubikvitinasy MeSH
- proteom MeSH
- ubikvitin * MeSH
The purpose of this manikin-based study was to determine the percentage penetrations of nine CE-marked filtering facepiece respirator models (two samples from each) from filtering classes FFP1, FFP2, and FFP3 and to demonstrate by an independent measurement method the disadvantages and shortcomings of the currently valid European Norm (EN 149:2001) for filtering facepieces. All of the filtering facepieces were evaluated size-selectively in an experimental chamber using charge-neutralized monodisperse ammonium sulfate in 9 sizes ranging from 20-400 nm of count median diameter (CMD) under flowrate of 95 L/min. The results were then compared to the previous study concerning penetrations of 47-mm diameter filters cut from the filtering material of identical filtering facepieces. Although these two experimental methods for measuring penetrations of filtering materials from filtering facepieces are in good agreement (R2 = 0.91), the results show within-respirator variations in all three filtering classes (5.5-19.3% for all FFRs in FFP1, 2.8-8.5% in FFP2, and 0.1-2.8% in FFP3). The most penetrating particle size (MPPS) in this study was found to be in the range of 25-65 nm (CMD), which is in agreement with the range of 30-60 nm found in the previous study. Moreover, 7 out of 9 FFR models reached higher penetrations from manikin-based respirator measurements than during measurements of filters from the respective respirators. Furthermore, penetration levels increased up to ∼50% when the respirator was not sealed around the face of the manikin, indicating that the real protection level provided by these filtering facepieces may be even lower if the respirator does not fit perfectly. Considering that poor filtration efficiency and poor fit may increase under real work conditions, the particle penetration is even higher than was found in this study. Therefore, the CE-marked respirators examined in this study may not be efficient in providing the expected level of protection for workers exposed to nanoparticles.
- Klíčová slova
- CE-marked respirator, EN 149, manikin-based study, monodisperse ammonium sulfate, size-resolved penetration,
- MeSH
- filtrace normy MeSH
- inhalační expozice prevence a kontrola MeSH
- modely anatomické rozkládací * MeSH
- nanočástice MeSH
- pevné částice analýza MeSH
- prostředky na ochranu dýchání normy MeSH
- síran amonný MeSH
- testování materiálů MeSH
- velikost částic * MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- pevné částice MeSH
- síran amonný MeSH
This review focuses on the latest development of microseparation electromigration methods in capillaries and microfluidic devices coupled with MS for detection and identification of important analytes. It is a continuation of the review article on the same topic by Kleparnik (Electrophoresis 2015, 36, 159-178). A wide selection of 161 relevant articles covers the literature published from June 2014 till May 2016. New improvements in the instrumentation and methodology of MS interfaced with capillary or microfluidic versions of zone electrophoresis, isotachophoresis, and isoelectric focusing are described in detail. The most frequently implemented MS ionization methods include electrospray ionization, matrix-assisted desorption/ionization and inductively coupled plasma ionization. Although the main attention is paid to the development of instrumentation and methodology, representative examples illustrate also applications in the proteomics, glycomics, metabolomics, biomarker research, forensics, pharmacology, food analysis, and single-cell analysis. The combinations of MS with capillary versions of electrochromatography, and micellar electrokinetic chromatography are not included.
- Klíčová slova
- CE, Electrospray, MS, Microfluidic devices,
- MeSH
- analýza jednotlivých buněk metody MeSH
- analýza potravin metody MeSH
- biologické markery analýza MeSH
- buněčné linie MeSH
- chromatografie metody MeSH
- elektroforéza kapilární přístrojové vybavení metody MeSH
- glykomika MeSH
- hmotnostní spektrometrie s elektrosprejovou ionizací přístrojové vybavení metody MeSH
- hmotnostní spektrometrie metody MeSH
- isoelektrická fokusace přístrojové vybavení metody MeSH
- laboratoř na čipu * MeSH
- lidé MeSH
- metabolomika metody MeSH
- spektrometrie hmotnostní - ionizace laserem za účasti matrice přístrojové vybavení metody MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
- Názvy látek
- biologické markery MeSH
This review provides an update on mercury speciation by CE. It includes a brief discussion on physicochemical properties, toxicity and transformation pathways of mercury species (i.e. methyl-, ethyl-, phenyl- and inorganic mercury) and outlines recent trends in Hg speciation by CE. CE is presented as a complementary technique to chromatographic separation techniques, especially in cases when speed, high efficiency and low sample volumes are required. The development of suitable sample preconcentration/isolation (sample stacking, ion exchange, liquid-liquid-liquid extraction, dual-cloud point extraction) to achieve low LODs for analysis of trace concentrations of mercury species in real samples is emphasized. Hyphenation of CE to element specific detectors (i.e. electrothermal atomic absorption spectrometry, atomic fluorescence spectrometry, inductively coupled plasma-optical emission spectrometry, inductively coupled plasma-mass spectrometry) is discussed as well as a potential of CE in interaction studies that may provide useful information on interaction of various Hg species with selected bio-macromolecules.
- MeSH
- chemická frakcionace MeSH
- elektroforéza kapilární přístrojové vybavení metody MeSH
- hmotnostní spektrometrie MeSH
- lidé MeSH
- organortuťnaté sloučeniny analýza chemie MeSH
- senzitivita a specificita MeSH
- sloučeniny rtuti analýza chemie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
- Názvy látek
- organortuťnaté sloučeniny MeSH
- sloučeniny rtuti MeSH
Effects of organic solvent type, pH value, and composition of donor/acceptor solution on the efficacy of electromembrane extraction (EME) were examined. For the first time, a comprehensive quantitative study, based also on measurements of electric charge passed through the EME system, was carried out, which demonstrates that apart from the pH value, also the nature of counter-ions in donor and acceptor solution plays a significant role in the electrically induced transfer of charged analytes across supported liquid membranes (SLMs). The EME transfer of model analytes correlated well with electrophoretic mobilities of inorganic cations, which were added to acceptor solutions during their alkalization with alkali metal hydroxides, and were highest for counter-cations with highest mobilities. Up to a 53-fold improvement of extraction efficiency was achieved for EMEs using optimized composition of donor (alkalized with KOH to pH 7) and acceptor (10 mM CsOH, pH 12) solutions. Six chlorophenols (CPs) were selected as model analytes due to the wide range of pH values that are required for their ionization and due to their high environmental relevance; quantitative measurements were carried out by CE with UV detection. Extraction recoveries of the six CPs ranged between 14 and 25% for 5 min EMEs at 150 V and 750 rpm across SLMs impregnated with 1-ethyl-2-nitrobenzene. Calibration curves were strictly linear (r(2) ≥ 0.999) in 0.01-10 μg/mL range, repeatability values of peak areas were between 0.7 and 5.6% and LODs for standard solutions and environmental samples were better than 5 ng/mL.
- Klíčová slova
- CE, Electromembrane extraction, Sample pretreatment, Supported liquid membrane,
- MeSH
- chemická frakcionace přístrojové vybavení metody MeSH
- chemické modely * MeSH
- chlorfenoly analýza chemie izolace a purifikace MeSH
- elektroforéza přístrojové vybavení metody MeSH
- limita detekce MeSH
- lineární modely MeSH
- membrány umělé * MeSH
- reprodukovatelnost výsledků MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- chlorfenoly MeSH
- membrány umělé * MeSH
Sample stacking techniques remain an important tool for enhancement of the selectivity and sensitivity of analyses in contemporary CZE. This contribution reviews new knowledge on this topic published since 2006. It is organized according to the operational principles used, which include concentration adjustment, application of a pH step, MEKC and sweeping, and transient ITP. Techniques combining several of these principles and comparative studies are also included.
- MeSH
- analýza potravin MeSH
- anorganické látky analýza MeSH
- chromatografie micelární elektrokinetická kapilární metody MeSH
- elektroforéza kapilární metody MeSH
- elektroforéza mikročipová metody MeSH
- elektroforéza metody MeSH
- hmotnostní spektrometrie metody MeSH
- koncentrace vodíkových iontů MeSH
- lidé MeSH
- senzitivita a specificita MeSH
- tělesné tekutiny chemie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
- Názvy látek
- anorganické látky MeSH
This review points out some important trends in the development of the detection techniques for small ions in CE. On the basis of selected literature references it briefly discusses some general requirements on detection techniques in CE. Various optical measurements, mass spectrometric approaches and electrochemical detection techniques are dealt with. Some specific features of microchip CE separation and detection are pointed out and possibilities of dual detection are mentioned. The principal parameters of the above detection techniques are then briefly compared.
- MeSH
- anorganické látky analýza chemie MeSH
- elektroforéza kapilární přístrojové vybavení metody MeSH
- elektroforéza mikročipová přístrojové vybavení metody MeSH
- fluorescenční barviva * MeSH
- hmotnostní spektrometrie metody MeSH
- ionty analýza chemie MeSH
- konduktometrie metody MeSH
- luminiscenční měření metody MeSH
- reprodukovatelnost výsledků MeSH
- senzitivita a specificita MeSH
- spektrofotometrie ultrafialová metody MeSH
- spektrometrie rentgenová emisní metody MeSH
- Publikační typ
- časopisecké články MeSH
- hodnotící studie MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
- Názvy látek
- anorganické látky MeSH
- fluorescenční barviva * MeSH
- ionty MeSH
