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Analysis of the Hydrated ions Clusters Impact on the Liquid/Liquid Interface
Mareček, Vladimír; Samec, Zdeněk; Trojánek, Antonín
2022 - English
Open circuit potential (OCP) measurements of the partition of tetrapentylammonium chloride (TPeACl) at the water/1,2-dichloroethane (DCE) interface reveal two remarkable processes. The first one is characterized by a decay of the OCP from its expected equilibrium value. This process has been ascribed to the extraction of the salt driven by its accumulation in the hydrated salt clusters in the DCE phase. The second process is characterized by the short-term potential spikes overlapping the long-term OCP records. These spikes are assumed to be associated with the collision and fusion of the hydrated salt clusters produced by the former process with the water/DCE interface.
Keywords:
Water/1,2-dichloroethane interface; Salt partition; Open circuit potential
Available on request at various institutes of the ASCR
Analysis of the Hydrated ions Clusters Impact on the Liquid/Liquid Interface
Open circuit potential (OCP) measurements of the partition of tetrapentylammonium chloride (TPeACl) at the water/1,2-dichloroethane (DCE) interface reveal two remarkable processes. The first one is ...
Manufacture of 3D Printed Microfluidic Channels and Their Characterization by Impedance Spectroscopy and Optical Microscopy Measurements
Štěrba, O.; Vaněčková, Eva; Choińska-Mlynarczyk, Marta; Navrátil, Tomáš; Kolivoška, Viliam
2022 - English
Fused deposition modeling 3D printing employing high-resolution extrusion nozzles and specialized manufacturing protocols have recently attracted attention as an inexpensive tool to create microfluidic devices. In this work, we have applied such an approach to create measurement cells with integrated microchannels of systematically varied dimensions. The real width of channels was inspected by two techniques, namely (A) impedance spectroscopy employing an aqueous sensing electrolyte and (B) optical microscopic imaging of silicone imprints hardened in the interior of printed structures. Both techniques have demonstrated that fused deposition modeling 3D printing enables precise manufacturing of channels with truly microfluidic dimensions.
Keywords:
Fused deposition modeling 3D printing; Lab-on-a-chip devices; Microfluidic channels; Impedance spectroscopy; Optical microscopy
Available on request at various institutes of the ASCR
Manufacture of 3D Printed Microfluidic Channels and Their Characterization by Impedance Spectroscopy and Optical Microscopy Measurements
Fused deposition modeling 3D printing employing high-resolution extrusion nozzles and specialized manufacturing protocols have recently attracted attention as an inexpensive tool to create ...
Mercury Film Screen-Printed Electrodes
Josypčuk, Bohdan; Šestáková, Ivana; Tvorynska, Sofiia
2022 - English
Mercury film screen-printed electrodes (MF-SPEs) were designed, prepared and tested for the first time as perspective representatives among SPEs that allow measuring at high negative potentials. For this purpose, the precise electrochemical (coulometric) preparation procedure for mercury deposition at the working electrode surface of the commercial silver-SPE was developed and a universal method of preparing MF-electrodes from different metal-SPEs was described. An optimal electrolyzer construction for the mercury deposition, electrolyte composition, electrolysis potential, and an activation of electrode surfaces were proposed. Determination of the zinc content in food supplement tablets was used for the MF-SPEs practical testing.
Keywords:
flow analysis; mercury film; screen-printed electrodes; electrochemistry
Available on request at various institutes of the ASCR
Mercury Film Screen-Printed Electrodes
Mercury film screen-printed electrodes (MF-SPEs) were designed, prepared and tested for the first time as perspective representatives among SPEs that allow measuring at high negative potentials. For ...
Spectroelectrochemistry of 1,10-phenantrolines Substituted by Pyrrolidine and Phenothiazine Redox-active Units
Sokolová, Romana; Wantulok, J.; Fiedler, Jan; Nycz, J.; Degano, I.
2022 - English
Compounds based on 1,10-phenanthroline (Phen) and their complexes are used in many fields, such as a stabilizing agent in the synthesis of nanoparticles, catalysts in homogeneous catalysis and as a semiconductor in organic light-emitting diodes (OLED) due to their coordination abilities. In this work, 1,10-phenanthrolines functionalized by pyrrolidine and phenothiazine units were studied by electrochemical methods. Cyclic voltammetry resulted in several oxidation and reduction voltammetric peaks. Structure-activity relationship was investigated using in situ spectroeletrochemistry, spectrophotometry, infrared spectroscopy and chromatography.
Keywords:
1,10-phenanthroline; Electrochemistry; Oxidation mechanism; Reduction mechanism
Available on request at various institutes of the ASCR
Spectroelectrochemistry of 1,10-phenantrolines Substituted by Pyrrolidine and Phenothiazine Redox-active Units
Compounds based on 1,10-phenanthroline (Phen) and their complexes are used in many fields, such as a stabilizing agent in the synthesis of nanoparticles, catalysts in homogeneous catalysis and as a ...
Construction and application of the amperometric uric acid biosensors based on the covalent immobilization of uricase by different strategies
Tvorynska, Sofiia; Barek, J.; Josypčuk, Bohdan
2021 - English
In this work, a promising combination of a biosensor based on the\nenzymatic mini-reactor with the detection principle of four-electron\nreduction of the consumed oxygen at highly negative potential has\nbeen developed for uric acid determination using flow injection\nanalysis. The construction of the biosensor provides a spatial\nsegregation of the biorecognition (uricase-based mini-reactor) and\ndetection (tubular detector of silver solid amalgam (TD-p-AgSA))\nparts. To find out the most appropriate enzyme immobilization\nprotocol, three different strategies of the covalent attachment for\nuricase from Bacillus fastidiosus have been compared. It was found\nthat the biosensor with the mini-reactor based on the covalent\nattachment of uricase via glutaraldehyde to -NH2 functionalized\nmesoporous silica powder MCM-41 showed extremely high stability\n(>1 year) and reusability (at least 600 measurements) The biosensor's\npractical applicability was confirmed by successful determination\nof uric acid in human urine.
Keywords:
amalgam electrode; amperometric biosensor; uric acid
Available in digital repository of the ASCR
Construction and application of the amperometric uric acid biosensors based on the covalent immobilization of uricase by different strategies
In this work, a promising combination of a biosensor based on the\nenzymatic mini-reactor with the detection principle of four-electron\nreduction of the consumed oxygen at highly negative potential ...
IMPOSING BIAXIAL STRAIN ON 2D LAYERED MATERIALS BY LIQUID-INDUCED SWELLING OF SUPPORTING POLYMER
Sampathkumar, Krishna; Pekárek, J.; Frank, Otakar
2021 - English
2D layered materials promise to revolutionize the field of electronics, photonics, optoelectronics, energy storage, and sensing, etc. 2D materials have exceptional mechanical properties, with critical elongation >10%. Employing the strain to manipulate the electronic structure of these 2D materials could lead to further improvement of their implementation in many aspects. The ease of manipulation of their electronic structure can be one of the critical factors for their utilization in photonic devices. Apart from the strain, which decreases (increases) the bandgap energy at the rate of similar to 100 meV under 1% of biaxial tension (compression), also the layer number causes bandgap energy change of, e.g., 0.5 eV between bulk (1.3 eV) and monolayer MoS2 (1.8 eV). In our work, we focus on using the swelling behavior of PMMA/SU8 polymer in methanol to impose the strain on 2D layered materials. In the first trials, we have shown that it is possible to reach a strain gradient from 0 to similar to 0.5% of biaxial strain via simple swelling of polymer substrates, both for graphene [1] and transition metal di-chalcogenides (TMDC) like MoS2. Raman spectroscopy was used to probe the lattice strain in the materials through measuring changes of vibrational frequencies, and photoluminescence was used to probe the strain-induced bandgap character and energy in TMDC at room temperature. The surface corrugation of the 2D material after the soaking was recorded with the help of atomic force microscope (AFM).
Keywords:
raman-spectroscopy; graphene; monolayer; bubbles; 2D material; graphene; tmdc; strain engineering; biaxial strain
Available in digital repository of the ASCR
IMPOSING BIAXIAL STRAIN ON 2D LAYERED MATERIALS BY LIQUID-INDUCED SWELLING OF SUPPORTING POLYMER
2D layered materials promise to revolutionize the field of electronics, photonics, optoelectronics, energy storage, and sensing, etc. 2D materials have exceptional mechanical properties, with critical ...
Looking into the Photo-stability of Eosin by Electrochemical Methods
Sabatini, F.; Sokolová, Romana; Degano, I.
2021 - English
Eosin Y is a synthetic organic dye belonging to the xanthene family. Its bright and fluorescent\npink hue attracted and intrigued the painters of the 19th century, who experimented eosin as\npigment lake (often called Geranium lake) in their paintings. Nevertheless, eosin coloration is\nas beautiful as unstable, and examples of work of arts with faded hues have been documented.\nEosin is not only photo-sensitive but also pH sensitive, making its study very complex. In this\nwork, the combination of electrochemical and spectroscopic techniques revealed to be effective\nfor correlating the physical evidence of eosin fading with its chemical degradation.
Keywords:
Eosin; Synthetic dye; UV-Vis spectroelectrochemistry
Available on request at various institutes of the ASCR
Looking into the Photo-stability of Eosin by Electrochemical Methods
Eosin Y is a synthetic organic dye belonging to the xanthene family. Its bright and fluorescent\npink hue attracted and intrigued the painters of the 19th century, who experimented eosin as\npigment ...
Oxidation Processes of N-methylguanines
Trnková, L.; Třísková, I.; Liška, Alan; Ludvík, Jiří
2021 - English
The oxidation processes of N-methylguanines were investigated in both experimental and\ntheoretical way. Voltammetric oxidation potentials of guanine and its methyl analogues,\nacquired on polymer pencil graphite electrode (pPeGE), were compared with the HOMO\n(SOMO) energies calculated by density functional (DFT) methods. Our study contributes to\nunderstanding not only the oxidation processes of methylated guanines but also their role in\nepigenetics.
Keywords:
Guanine; N-methylated guanine; Oxidation process
Available on request at various institutes of the ASCR
Oxidation Processes of N-methylguanines
The oxidation processes of N-methylguanines were investigated in both experimental and\ntheoretical way. Voltammetric oxidation potentials of guanine and its methyl analogues,\nacquired on polymer ...
3D printed materials for the electrochemical determination of biologically active compounds
Choińska, Marta Katarzyna; Navrátil, Tomáš; Hrdlička, Vojtěch
2021 - English
3D printing materials are relatively novel materials in electrochemistry,\nused for manufacturing of electrochemical cells, electrodes\netc. They have been widely used mainly for tailored, fast, inexpensive,\nand easy preparation of various equipment for analyses of\nbiologically active compounds. Various medicinal products and illicit\ndrugs belong to this broad group of analytes which need to be\nmonitored because of the possibility of (un)intentional overdose or\nrecreational consumption, which can cause serious side effects or\neven death. Due to this risk, we decided to focus our research on the\ndevelopment of new, sensitive, selective, and easily customizable 3D\nprinted sensors for the determination of some commonly used\nantidepressants, analgesics, and illicit drugs.
Keywords:
analgesics; antidepressants; voltammetric determination
Available on request at various institutes of the ASCR
3D printed materials for the electrochemical determination of biologically active compounds
3D printing materials are relatively novel materials in electrochemistry,\nused for manufacturing of electrochemical cells, electrodes\netc. They have been widely used mainly for tailored, fast, ...
ELECTROCHEMICAL STUDY OF CuSCN INORGANIC HOLE-TRANSPORT MATERIAL FOR SOLAR CELLS PREPARED BY ELECTRODEPOSITION FROM AQUEOUS SOLUTION
Vlčková Živcová, Zuzana; Mansfeldová, Věra; Bouša, Milan; Kavan, Ladislav
2021 - English
A comparative study is reported for electrodeposited copper(I) thiocyanate layers (ca. 500 nm) on two types of conductive/semiconductive substrates: i) carbon (boron-doped diamond_BDD, glass-like carbon_GC), and ii) carbon-free F-doped SnO2 conducting glass (FTO). SEM and Raman evidence that electrodeposition from aqueous solution results in homogenous CuSCN layers with dominant thiocyanate ion bounded to copper through its S-end (Cu−SCN bonding), as in spin-coated CuSCN layers. Electrochemical impedance spectroscopy (EIS) confirms the p-type semiconductivity of layers with a flatband potential from 0.1 to 0.18 V vs. Ag/AgCl depending on the substrate type, and the acceptor concentration (NA) of 5 x 1020cm-3 in all cases. The flatband potentials determined from Mott-Schottky plots (EIS) are in good agreement with the Kelvin probe measurements. The blocking quality of CuSCN layers was tested using Ru(NH3)63+/2+ redox probe. CuSCN deposited on BDD substrate exhibits better blocking properties compared to CuSCN deposited on FTO.
Keywords:
electrodeposition; CuSCN; hole transport material
Available in digital repository of the ASCR
ELECTROCHEMICAL STUDY OF CuSCN INORGANIC HOLE-TRANSPORT MATERIAL FOR SOLAR CELLS PREPARED BY ELECTRODEPOSITION FROM AQUEOUS SOLUTION
A comparative study is reported for electrodeposited copper(I) thiocyanate layers (ca. 500 nm) on two types of conductive/semiconductive substrates: i) carbon (boron-doped diamond_BDD, glass-like ...
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