Ústav analytické chemie

Nejnovější přírůstky:
2021-03-28
00:00
Deposition of dried colloidal suspension via nanoelectrospray
Jonas, Vladimír ; Týčová, Anna ; Přikryl, Jan ; Kotzianová, A. ; Velebný, V. ; Foret, František
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.

Úplný záznam
2021-03-07
00:01
Detekce a identifikace aflatoxinů pomocí přenosného kapalinového chromatografu pro potřeby kontroly zákazu biologických zbraní
Šesták, Jozef ; Lunerová, K.
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.

Úplný záznam
2020-12-03
22:56
Quick determination of compounds contained in caraway (Carum carvi L.) by a method usable in agricultural practice
Horáčková, L. ; Pluháčková, H. ; Bradáčová, M. ; Kudláčková, Barbora
Caraway is a very important agricultural commodity whose quality is determined by parameters such as dry matter, essential oil content and composition, especially the ratio of its two major components carvone and limonene. Appropriate method for their analysis is given in the Cesky lekopis (2017), however, this method is rather time-consuming, costly and demands large quantity of sample. The use of a NIR spectrometer could be a viable alternative, it is much faster and cheaper, as can be clearly seen from the comparison of both methods in this paper. In the time aspect, it's saving from many hours to a few minutes. Newly presented method could potentially be more accessible to agricultural companies who need quick quality verification of their product before taking it to the market from the viewpoint of final product quality not just the quantity, which, in most cases, is nowadays a current state of practice.

Úplný záznam
2020-12-03
22:56
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
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.

Úplný záznam
2020-12-03
22:56
Photon-upconversion scanner for multiplexed imaging
Hlaváček, Antonín ; Křivánková, Jana ; Foret, František
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.

Úplný záznam
2020-12-03
22:56
Fast and highly sensitive laser scanner for recording photon-upconversion luminiscence from planar surfaces
Hlaváček, Antonín ; Křivánková, Jana ; Foret, František
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.

Úplný záznam
2020-12-03
22:56
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.
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.

Úplný záznam
2020-12-03
22:53
Photochemical vapor generation of cobalt for detection by inductively coupled plasma mass spectrometry
Vyhnanovský, Jaromír ; Musil, Stanislav
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.

Úplný záznam
2020-12-03
22:53
Chemical vapor generation of cadmium for analytical atomic spectrometry
Sagapova, Linda ; Kodríková, Barbora ; Svoboda, Milan ; Musil, Stanislav ; Kratzer, Jan
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.

Úplný záznam
2020-12-03
22:53
Photochemical vapour generation of bismuth coupled with atomic fluorescence spectrometry
Štádlerová, Barbora ; Vyhnanovský, Jaromír ; Dědina, Jiří ; Musil, Stanislav
Atomization of bismuthane in the flame-in-gas-shield atomizer by photochemical vapour generation coupled with atomic fluorescence spectrometry.

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