Number of found documents: 453
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Detekce a identifikace aflatoxinů pomocí přenosného kapalinového chromatografu pro potřeby kontroly zákazu biologických zbraní
Šesták, Jozef; Lunerová, K.
2020 - Czech
Metodika popisuje způsob screeningové detekce a identifikace vybraných mykotoxinů aflatoxinů (aflatoxinů B1, B2, G1 a G2), ochratoxinů A, B a zearalenonu pomocí přenosného miniaturizovaného kapalinového chromatografu (miniLC) s UV/VIS a fluorescenčním detektorem (FLD). Cílem metodiky je poskytnout rychlou metodu pro zjištění/vyloučení přítomnosti uvedených mykotoxinů v neznámém vzorku. V případě pozitivního zjištění je nutné u daného vzorku provést potvrzení identity látek pomocí dalších instrumentálních metod (např. LC-MS). Metodika je určena zejména pro potřeby technické podpory SÚJB při kontrolní a dozorové činnosti v oblasti dodržování Zákona č. 281/1997 Sb. Method describes screening detection and identification of selected mycotoxins aflatoxins (aflatoxins B1, B2, G1 and G2), ochratoxins A, B and zearalenon by means of portable miniaturzed capillary liquid chromatograph (miniLC) with UV/VIS and fluorescence detector (FLD). The aim of the method is to provide rapid screening method for finding/excluding the presence of given mycotoxins in unknown samples. In case of positive finding, it is necessary to perform confirmation analysis using other instrumental methods (e. g. LC-MS). The method is intended namely for the needs of technical support of the State Office for Nuclear Safety for control and supervising activities in field of execution of the Act No. 281/1997 Coll (Biological Act). Keywords: miniaturized capillary chromatograph; aflatoxins; portable liquid chromatograph Available on request at various institutes of the ASCR
Detekce a identifikace aflatoxinů pomocí přenosného kapalinového chromatografu pro potřeby kontroly zákazu biologických zbraní

Metodika popisuje způsob screeningové detekce a identifikace vybraných mykotoxinů aflatoxinů (aflatoxinů B1, B2, G1 a G2), ochratoxinů A, B a zearalenonu pomocí přenosného miniaturizovaného ...

Šesták, Jozef; Lunerová, K.
Ústav analytické chemie, 2020

Photochemical vapor generation of cobalt for detection by inductively coupled plasma mass spectrometry
Vyhnanovský, Jaromír; Musil, Stanislav
2020 - English
Volatile species of cobalt were generated in a flow-injection system, employing a high-efficiency flow-through UV photoreactor and a formic acid based medium. Optimal generation conditions were found as 10% (v/v) formic acid and 4 mol/L ammonium formate at a flow rate of 4 ml/min. Keywords: photochemical vapor generation; cobalt; inductively coupled plasma mass spectrometry Available in digital repository of the ASCR
Photochemical vapor generation of cobalt for detection by inductively coupled plasma mass spectrometry

Volatile species of cobalt were generated in a flow-injection system, employing a high-efficiency flow-through UV photoreactor and a formic acid based medium. Optimal generation conditions were found ...

Vyhnanovský, Jaromír; Musil, Stanislav
Ústav analytické chemie, 2020

Photon-upconversion nanoparticles for single-mocule immunosensing of cancer biomarkers and bacteria
Farka, Z.; Mickert, M. J.; Hlaváček, Antonín; Poláchová, V.; Kostiv, Uliana; Pastucha, M.; Horák, Daniel; Gorris, H. H.; Skládal, P.
2020 - English
The recent progress in the field of immunoassays has been driven by introduction of various kinds of nanomaterials. In particular, photon-upconversion nanoparticles (UCNPs) proved to be excellent immunoassay labels due to their ability to emit light of shorter wavelengths under near-infrared excitation (anti-Stokes emission), which prevents autofluorescence, minimizes light scattering, and thus reduces the optical background interference. These unique photoluminescent properties allow counting of individual biomolecules labeled with UCNPs by conventional wide-field epiluminescence microscopy and enable the development of single-molecule (digital) immunoassays. We have introduced a novel label based on UCNPs conjugated with streptavidin via poly(ethylene glycol) and applied it in a digital upconversion-linked immunosorbent assay (ULISA) for the detection of a cancer biomarker prostate specific antigen (PSA). The digital readout based on counting of individual immunocomplexes improved the sensitivity 16× compared to conventional analog readout and allowed to reach a limit of detection (LOD) of 23 fg·mL−1 (800 aM). Human serum samples were successfully analyzed achieving an excellent correlation with electrochemiluminescence reference method. The conjugates of UCNPs with streptavidin are also suitable for the detection of pathogenic bacterium Melissococcus plutonius, the causative agent of honeybee disease European foulbrood. The ULISA assay provided an LOD of 340 CFU·mL−1 and successfully analyzed real samples of bees, larvae and bottom hive debris. Due to the high reliability and relatively simple detection scheme, the digital ULISA can pave the way for a new generation of digital immunoassays with a strong potential for commercialization. Keywords: single-molecule detection; photon-upconversion nanoparticle; bioconjugation Available in digital repository of the ASCR
Photon-upconversion nanoparticles for single-mocule immunosensing of cancer biomarkers and bacteria

The recent progress in the field of immunoassays has been driven by introduction of various kinds of nanomaterials. In particular, photon-upconversion nanoparticles (UCNPs) proved to be excellent ...

Farka, Z.; Mickert, M. J.; Hlaváček, Antonín; Poláchová, V.; Kostiv, Uliana; Pastucha, M.; Horák, Daniel; Gorris, H. H.; Skládal, P.
Ústav analytické chemie, 2020

Fast and highly sensitive laser scanner for recording photon-upconversion luminiscence from planar surfaces
Hlaváček, Antonín; Křivánková, Jana; Foret, František
2020 - English
Photon-upconversion nanoparticles (UCNPs) are lanthanide-doped nanocrystals that can be excited by nearinfrared light and emit photon-upconversion luminescence of shorter wavelengths. Advantages of UCNPs include near-infrared excitation, multiple and narrow emission bands, negligible autofluorescence and high stability, which make UCNPs ideal luminescence label for use in biological and chemical assays. These assays - e.g. upconversion-linked immunosorbent assay, western blot, lateral flow assay, gel electrophoresis, thin layer chromatography - commonly require the scanning of a planar surface with a high spatial resolution and an excellent sensitivity. The availability of commercial equipment is recently limited because of the novelty of the photon-upconversion phenomenon. Therefore, we report on the construction of photon-upconversion laser scanner. The scanner consists of a laser scanning head, which is attached to a xy-moving stage. The scanning head itself is constructed as an epiluminescence detector with excitation wavelength of 976 nm. A CCD array spectroscope is connected to the laser head and serves as a sensitive detector of photon-upconversion luminescence. The scanner possesses a spatial resolution of 200 μm, the scanning rate is up to 57 points per second and the sensitivity reaches down to single photon-upconversion nanoparticle. Keywords: photon-upconversion; nanoparticle; laser scanner; hyperspectral imaging Available in digital repository of the ASCR
Fast and highly sensitive laser scanner for recording photon-upconversion luminiscence from planar surfaces

Photon-upconversion nanoparticles (UCNPs) are lanthanide-doped nanocrystals that can be excited by nearinfrared light and emit photon-upconversion luminescence of shorter wavelengths. Advantages of ...

Hlaváček, Antonín; Křivánková, Jana; Foret, František
Ústav analytické chemie, 2020

Photon-upconversion scanner for multiplexed imaging
Hlaváček, Antonín; Křivánková, Jana; Foret, František
2020 - English
In analytical chemistry, multiplexed assays facilitate parallel detection of analytes. The multiplexing reduces the consumption of sample, reagents, and other resources and can be applied for medical diagnostics, the studies of biomolecule interactions, single-cell and singlemolecule assays, environmental monitoring, pathogen detection, multiparameter chemical and biological assays and screening of chemical libraries. Keywords: photon-upconversion scanner; photon-upconversion nanoparticles; droplet microfluidics Fulltext is available at external website.
Photon-upconversion scanner for multiplexed imaging

In analytical chemistry, multiplexed assays facilitate parallel detection of analytes. The multiplexing reduces the consumption of sample, reagents, and other resources and can be applied for medical ...

Hlaváček, Antonín; Křivánková, Jana; Foret, František
Ústav analytické chemie, 2020

Surface modification of nanoparticles for sustaining sensitivity of surface-enhanced raman spectrometric measurements in salinated environment
Týčová, Anna; Přikryl, Jan; Vaňhara, P.; Klepárník, Karel; Foret, František
2020 - English
Surface-enhanced Raman spectrometry (SERS) represents a powerful method for analysis of a broad spectrum of analytes ranging from inorganic ions to biomolecules of high complexity. It combines the potential\nof Raman spectrometry for a definite identification of an analyte with remarkable sensitivity achieved by the surface enhancement effect occurring on metal nanoparticles. While low ionic strength influences positively\nthe sensitivity of the SERS measurement, a higher level of inorganic salts leads to fast ruining of colloidal character, which completely devastates the effect of the surface enhancement. The common stabilization of\nnanoparticles by a layer of polymers has a negative impact on the SERS sensitivity since it shields the nanoparticle surface from the analytes. In this work, we aim at the development of the bi-ligand system of\nnanoparticles surface modification for improved stability of colloid in saline solution at sustaining the potential for sensitive SERS analyses. The proposed system relies on the binding of 3-mercaptopropionic acid and\nthiolated polyethylene glycol in a suitable ratio onto the nanoparticle surfaces. While the short chains of the acid sustain the accessibility of the surface for analytes, the polymeric structures act as a steric barrier\npreventing colloid aggregation. Keywords: bi-ligand; nanoparticle; saline solution; surface-enhanced Raman spectrometry Available at various institutes of the ASCR
Surface modification of nanoparticles for sustaining sensitivity of surface-enhanced raman spectrometric measurements in salinated environment

Surface-enhanced Raman spectrometry (SERS) represents a powerful method for analysis of a broad spectrum of analytes ranging from inorganic ions to biomolecules of high complexity. It combines the ...

Týčová, Anna; Přikryl, Jan; Vaňhara, P.; Klepárník, Karel; Foret, František
Ústav analytické chemie, 2020

Photochemical vapour generation of bismuth coupled with atomic fluorescence spectrometry
Štádlerová, Barbora; Vyhnanovský, Jaromír; Dědina, Jiří; Musil, Stanislav
2020 - English
Atomization of bismuthane in the flame-in-gas-shield atomizer by photochemical vapour generation coupled with atomic fluorescence spectrometry. Keywords: atomic fluorescence spectrometry; bismuth; photochemical vapour generation Available in digital repository of the ASCR
Photochemical vapour generation of bismuth coupled with atomic fluorescence spectrometry

Atomization of bismuthane in the flame-in-gas-shield atomizer by photochemical vapour generation coupled with atomic fluorescence spectrometry.

Štádlerová, Barbora; Vyhnanovský, Jaromír; Dědina, Jiří; Musil, Stanislav
Ústav analytické chemie, 2020

DNA damage induced by occupational exposure to copper oxide nanoparticles
Rössner st., Pavel; Pelcová, D.; Elzeinová, Fatima; Mikuška, Pavel; Večeřa, Zbyněk; Coufalík, Pavel; Vlčková, Š.; Fenclová, Z.; Rossnerová, Andrea
2020 - English
Copper oxide nanoparticles (CuO NPs) have a widespread use in industry, chemistry, in production of electronic devices and as an antimicrobial agent. Although copper is an important biogenic element, CuO NPs are toxic with the ability to induce oxidative stress, apoptosis, cell cycle arrest or DNA damage. For humans, the inhalation route is the most common way of exposure to CuO NPs. In the body, CuO NPs may be either deposited in the lungs, or transported to other organs. Their presence usually causes oxidative stress or inflammatory responses, consequently leading to DNA damage. In this study, we investigated the effect of CuO NPs inhalation on DNA damage in a group of researches conducting animal exposure experiments. The subjects were exposed to various metal oxide nanoparticles, including CuO NPs, by inhalation for an average of 4.9 ± 0.4 years. The average mass concentration of Cu in the air during the experiment was 7.3 ± 3.2 ng/m3. Subjects not exposed to nanoparticles served as a control group. We applied micronucleus assay using Human Pan Centromeric probes to detect DNA damage and to distinguish between the frequency of centromere positive (CEN+) and centromere negative (CEN−) micronuclei (MN) in the binucleated cells. We\ndid not find differences between both groups for either mean MN frequency (10.38 ± 2.50 vs. 11.88 ± 3.01 MN/1000 binucleated cells), or CEN+/CEN- ratio (58%/42% vs. 55%/45%), for the exposed and controls, respectively. In conclusion, inhalation of CuO NPs at this low-level exposure had no effect on chromosomal losses and/or breaks. Keywords: copper oxide nanoparticles; inhalation; DNA damage Available in digital repository of the ASCR
DNA damage induced by occupational exposure to copper oxide nanoparticles

Copper oxide nanoparticles (CuO NPs) have a widespread use in industry, chemistry, in production of electronic devices and as an antimicrobial agent. Although copper is an important biogenic element, ...

Rössner st., Pavel; Pelcová, D.; Elzeinová, Fatima; Mikuška, Pavel; Večeřa, Zbyněk; Coufalík, Pavel; Vlčková, Š.; Fenclová, Z.; Rossnerová, Andrea
Ústav analytické chemie, 2020

Deposition of dried colloidal suspension via nanoelectrospray
Jonas, Vladimír; Týčová, Anna; Přikryl, Jan; Kotzianová, A.; Velebný, V.; Foret, František
2020 - English
Electrospray is a relatively well-established tool for the deposition of nanoparticles. In this work, we use nanoelectrospray (nES) operating at flow rates down to tens of nanoliters per minute. As a result, the formed aerosol consists of very small droplets quickly drying during the flight towards a counter-electrode. Therefore, we obtained deposits of increased homogeneous distribution without an undesirable coffee-ring effect. Moreover, the character of the aerosol plume is only a few millimeters wide, so it allows good control over the deposit localization. Keywords: nanoparticles; nanoelectrospray; silver Fulltext is available at external website.
Deposition of dried colloidal suspension via nanoelectrospray

Electrospray is a relatively well-established tool for the deposition of nanoparticles. In this work, we use nanoelectrospray (nES) operating at flow rates down to tens of nanoliters per minute. As a ...

Jonas, Vladimír; Týčová, Anna; Přikryl, Jan; Kotzianová, A.; Velebný, V.; Foret, František
Ústav analytické chemie, 2020

Chemical vapor generation of cadmium for analytical atomic spectrometry
Sagapova, Linda; Kodríková, Barbora; Svoboda, Milan; Musil, Stanislav; Kratzer, Jan
2020 - English
Chemical vapor generation of cadmium volatile compounds was optimized, several reaction modifiers based on inorganic salts and complexes of CrIII+, CoII+, TiIII+, TiIV+ were tested. Their use resulted in 4-5 times enhancement in sensitivity, reflected also in corresponding increase of generation efficiency and better repeatability. Generation efficiency was determined from a comparison between sensitivities obtained with chemical vapor generation and conventional solution nebulization, both simultaneously coupled with inductively coupled plasma mass spectrometry. The identity of the generated cadmium compounds was identified. Keywords: cadmium; chemical vapor generation; atomic absorption spectrometry Available in digital repository of the ASCR
Chemical vapor generation of cadmium for analytical atomic spectrometry

Chemical vapor generation of cadmium volatile compounds was optimized, several reaction modifiers based on inorganic salts and complexes of CrIII+, CoII+, TiIII+, TiIV+ were tested. Their use resulted ...

Sagapova, Linda; Kodríková, Barbora; Svoboda, Milan; Musil, Stanislav; Kratzer, Jan
Ústav analytické chemie, 2020

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