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Proceedings of APCE-CECE-ITP-IUPAC 2022
Foret, František ; Lavická, Jana ; Chung, D. S. ; Drobníková, Iveta ; Přikryl, Jan ; Lee, H.
The joint International Interdisciplinary Conference of Chemical Analysis, APCE-CECE-ITP-IUPAC 2022, comprising the 18th Asia Pacific International Symposium on Microscale Separations and Analyses, the 17th International Interdisciplinary Meeting on Bioanalysis, the 28th International Symposium on Electro- and Liquid Phase-Separation Techniques, and IUPAC Special Symposia by Division of Chemistry and the Environment, provided full texts of 108 oral and 54 poster presentations. The attached conference proceedings, edited by highly cited scientists, document the quality of the meeting. Similarly to previous years, the lectures were given by distinguished scientists. The list of speakers as well as more detailed information about the conference can be found on its permanent web at www.ce-ce.org or in the proceedings published in Separations (https://doi.org/10.3390/separations10020109).
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Epitachophoretic preconcentration of proteins
Hrušková, Helena ; Voráčová, Ivona ; Foret, František
In this work, we present a developed method for preconcentration of standards of proteins cytochrome c, myoglobin, and hemoglobin. Firstly, the electrolyte system was selected and optimized to provide low analysis time, narrow shape of the protein zone, and eliminate overheating at the center of the device. In the next step, the developed method was tested on the preconcentration of proteins: cytochrome c, myoglobin, and hemoglobin. After several adjustments myoglobin and hemoglobin were also uccessfully preconcentrated. After evaluation of pilot results, this technique provides up to fiftyfold preconcentration and recovery of over 70 % for each protein. The next plan is to preconcentrate proteins from complex biological matrices such as urine or blood plasma.
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Nanospray processing of silver nanoparticles for formation of dried deposits
Týčová, Anna ; Jonas, Vladimír ; Přikryl, Jan ; Kotzianová, A. ; Velebný, V. ; Foret, František
Nanospray transfers liquid into an aerosol via electrostatic forces created between an emitter and a counter electrode. Herein, we present compact laboratory-made instrumentation for nanospray-processing of silver colloid. The instrumentation is based on the pressurized polysulfone chamber fixing a disposable vial with an immersed platinum electrode and a long fused silica capillary supplying the sprayed liquid to the emitter. The combination of low flow rates (70 nL/min) with a sharp emitter, fabricated on a 3D printed grinding station, resulted in a fine aerosol. The low volume of released droplets allowed full evaporation of water during their flight towards the counter electrode without any need for drying gas or the addition of volatile solvents. The constructed device was successfully used for the deposition of water-free silver colloid without any requirement of its pretreatment. The deposition of completely dried nanoparticles on planar substrates eliminated undesirable coffee ring effect and deposits of increased homogeneity could be obtained. Electron microscopy confirmed no significant changes in the character of nanospray-processed nanoparticles. Finally, we also investigated several approaches for the improvement of the surface density of nanoparticles on the substrate at preserved time scale.
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Computer assisted development of a pneumatic electrospray nebulizer
Járvás, G. ; Szigeti, M. ; Grym, Jakub ; Foret, František ; Guttman, A.
In this study we demonstrate how computer simulations can assist the development of a novel microfabricated pneumatic electrospray nebulizer. The microdevice under consideration is designed for electrospray mass spectrometry interfacing without the need to fabricate an electrospray needle. This new interfacing strategy requires comprehensive evaluation of the differently designed chip layouts. The flow evaluation was supported by computational fluid dynamics simulations. It was proved with experimental validation of the simulation results that the developed models were practical tools for the numerical investigation of the separations-ESI-MS coupling.
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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.
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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.
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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.
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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
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.
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Epitachophoretic separation and concentration of large volume samples
Voráčová, Ivona ; Foret, František ; Datinská, Vladimíra ; Novotný, Jakub ; Gheibi, P. ; Berka, J. ; Astier, Y.
There has been a growing interest in developing isotachophoretic protocols for concentration and purification of DNA as an alternative to the solid phase extraction protocols of DNA preparation. Also concentration of DNA from large volume samples is required. We have developed a new device suitable for separation, concentration and collection of ions from several milliliter sample volumes into microliter fractions. We have used a discontinuous electrolyte system comprising of the leading and terminating electrolytes utilized for concentration of samples containing DNA fragments. The method is simple, fast with high concentration factor and without extensive surface interactions.
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