One of the most widely investigated functions of the brain is vision. Whereas special attention is often paid to motion detection and its modulation by attention, comparatively still little is known about the structural background of this function. We therefore, examined the white matter microstructural background of coherent motion detection. A random-dot kinematogram paradigm was used to measure the sensitivity of healthy individuals׳ to movement coherence. The potential correlation was investigated between the motion detection threshold and the white matter microstructure as measured by high angular resolution diffusion MRI. The Track Based Spatial Statistics method was used to address this correlation and probabilistic tractography to reveal the connection between identified regions. A significant positive correlation was found between the behavioural data and the local fractional anisotropy in the posterior part of the right superior frontal gyrus, the right juxta-cortical superior parietal lobule, the left parietal white matter, the left superior temporal gyrus and the left optic radiation. Probabilistic tractography identified pathways that are highly similar to the segregated attention networks, which have a crucial role in the paradigm. This study draws attention to the structural determinant of a behavioural function.

• Klíčová slova
• DTI, MRI, Motion detection, Vision, White matter microstructure,
• MeSH
• anizotropie MeSH
• bílá hmota anatomie a histologie   fyziologie   MeSH
• diferenční práh fyziologie   MeSH
• difuzní magnetická rezonance MeSH
• dospělí MeSH
• lidé MeSH
• mladý dospělý MeSH
• mozek anatomie a histologie   fyziologie   MeSH
• nervové dráhy anatomie a histologie   fyziologie   MeSH
• psychofyzika MeSH
• světelná stimulace MeSH
• teorie detekce signálu fyziologie   MeSH
• vnímání pohybu fyziologie   MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Capillary electrophoresis with capacitively coupled contactless conductivity detection (CE-C4D) was employed for fast determination of meldonium (MEL) in urine samples. Background electrolyte consisting of 2M acetic acid (pH 2.3) was used for separation of MEL from cationic compounds present in urine samples and the overall analysis time was less than 4min per sample. Direct injection of urine samples was possible after 1:9 dilution with deionized water. This simple sample pretreatment was sufficient to eliminate possible matrix effects on CE performance and allowed for precise and sensitive determination of free MEL in urine. Excellent linearity (r2≥0.9998) was obtained for two concentration ranges, 0.02-4μgmL-1 and 2-200μgmL-1, by simply changing injection time from 10 to 2s without the need for additional dilution of urine samples. Limit of detection was 0.015μgmL-1 and average recoveries from urine samples spiked at 0.02-123.5μgmL-1 MEL ranged from 97.6-99.9%. Repeatability of migration times and peak areas was better than 0.35% and 4.2% for intraday and 0.95% and 4.7% for interday measurements, respectively. The above reported data proved good applicability of the CE-C4D method to determination of various MEL concentrations in urine samples and good long-term performance of the analytical system. The method might be particularly useful in analyses of large batches of samples for initial testing of MEL-positive vs. MEL-negative urine samples.

• Klíčová slova
• Capillary electrophoresis, Contactless conductivity detection, Meldonium, Mildronate, Urine,
• MeSH
• doping ve sportu MeSH
• elektrická vodivost MeSH
• elektroforéza kapilární metody   MeSH
• elektrolyty MeSH
• lidé MeSH
• methylhydraziny moč   MeSH
• odhalování abúzu drog metody   MeSH
• voda MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• 3-(2,2,2-trimethylhydrazine)propionate MeSH Prohlížeč
• elektrolyty MeSH
• methylhydraziny MeSH
• voda MeSH

Water, ubiquitous in analytical methods, is renowned for its fluorescence quenching properties, influencing techniques like fluorescence spectrophotometry or techniques with fluorescence detection. This study explores the impact of water (H₂O) substitution for heavy water (D₂O) on the fluorescence behavior of anthraquinones and anthracyclines. Anthraquinones and anthracyclines play crucial roles in pharmacy, serving as essential components in various therapeutic formulations, particularly in cancer treatment and other pharmacological interventions. Capillary electrophoresis (CE) with heavy water as the background electrolyte (BGE) solvent offers superior sensitivity to the separation and detection of these analytes. Experimental results demonstrate the improved detection limits and separation efficiency of selected anthraquinones rhein (RH), aloe-emodin (AE), and anthracyclines doxorubicin (DOX), epirubicin (EPI) and daunorubicine (DAU) in heavy water-based buffers, highlighting the potential of heavy water in advancing analytical chemistry.

• Klíčová slova
• Anthracyclines, Anthraquinones, Capillary electrophoresis, Fluorescence detection, Heavy water,
• MeSH
• anthrachinony * chemie   analýza   MeSH
• antracykliny analýza   chemie   MeSH
• elektroforéza kapilární * metody   MeSH
• fluorescenční spektrometrie * metody   MeSH
• limita detekce MeSH
• oxid deuteria chemie   MeSH
• voda chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• anthrachinony * MeSH
• antracykliny MeSH
• oxid deuteria MeSH
• rhein MeSH Prohlížeč
• voda MeSH

To ensure food safety and to prevent unnecessary foodborne complications this study reports fast, fully automated process for histamine determination. This method is based on magnetic separation of histamine with magnetic particles and quantification by the fluorescence intensity change of MSA modified CdSe Quantum dots. Formation of Fe2O3 particles was followed by adsorption of TiO2 on their surface. Magnetism of developed probe enabled rapid histamine isolation prior to its fluorescence detection. Quantum dots (QDs) of approx. 3 nm were prepared via facile UV irradiation. The fluorescence intensity of CdSe QDs was enhanced upon mixing with magnetically separated histamine, in concentration-dependent manner, with a detection limit of 1.6 μM. The linear calibration curve ranged between 0.07 and 4.5 mM histamine with a low LOD and LOQ of 1.6 μM and 6 μM. The detection efficiency of the method was confirmed by ion exchange chromatography. Moreover, the specificity of the sensor was evaluated and no cross-reactivity from nontarget analytes was observed. This method was successfully applied for the direct analysis of histamine in white wine providing detection limit much lower than the histamine maximum levels established by EU regulation in food samples. The recovery rate was excellent, ranging from 84 to 100% with an RSD of less than 4.0%. The main advantage of the proposed method is full automation of the analytical procedure that reduces the time and cost of the analysis, solvent consumption and sample manipulation, enabling routine analysis of large numbers of samples for histamine and highly accurate and precise results.

• Klíčová slova
• Food safety, Histamine, Ion exchange chromatography, Maghemite, Quantum dots,
• MeSH
• fluorescence MeSH
• fluorescenční barviva chemie   MeSH
• fluorescenční spektrometrie metody   MeSH
• histamin analýza   MeSH
• kontaminace potravin analýza   MeSH
• kovové nanočástice chemie   MeSH
• kvantové tečky chemie   MeSH
• limita detekce MeSH
• magnetické jevy MeSH
• silany chemie   MeSH
• sloučeniny kadmia chemie   MeSH
• telur chemie   MeSH
• titan chemie   MeSH
• víno analýza   MeSH
• železité sloučeniny chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• cadmium telluride MeSH Prohlížeč
• ferric oxide MeSH Prohlížeč
• fluorescenční barviva MeSH
• histamin MeSH
• silany MeSH
• sloučeniny kadmia MeSH
• telur MeSH
• tetraethoxysilane MeSH Prohlížeč
• titan MeSH
• titanium dioxide MeSH Prohlížeč
• železité sloučeniny MeSH

The new screening method for rapid evaluation of major phenolic compounds in apples has been developed. Suitability of coupling HPLC/UHPLC separation with the diode-array detection and universal charged aerosol detection with respect to the presence of interfering substances was tested. Characteristics of both detection techniques were compared and method linearity, limits of detection and quantitation, and selectivity of them determined. Student t-test based on slopes of calibration plots was applied for the detailed comparison. The diode-array detection provided the best results regarding sensitivity and selectivity of the developed method in terms of evaluation of phenolics profiles. The response of the charged aerosol detector was negatively affected by co-eluting substances during rapid-screening analyses. Coulometric detection was used for advanced characterization of extracts in terms of antioxidant content and strength to obtain more complex information concerning sample composition. This detection also allowed evaluation of unidentified compounds with antioxidant activity. HPLC/UHPLC separation using a combination of diode-array and coulometric detectors thus represented the best approach enabling quick, yet complex characterization of bioactive compounds in apples.

• Klíčová slova
• antioxidants, apple extracts, charged aerosol detection, complex matrices, coulometric detection, detection sensitivity, diode-array detection, phenolic compounds,
• MeSH
• aerosoly chemie   MeSH
• antioxidancia chemie   MeSH
• chromatografie metody   MeSH
• elektrochemie metody   MeSH
• fenol chemie   MeSH
• fenoly analýza   MeSH
• kalibrace MeSH
• limita detekce MeSH
• Malus metabolismus   MeSH
• potravinářská technologie MeSH
• reprodukovatelnost výsledků MeSH
• vysokoúčinná kapalinová chromatografie metody   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• aerosoly MeSH
• antioxidancia MeSH
• fenol MeSH
• fenoly MeSH

We present a compact surface plasmon resonance (SPR) biosensor for the detection of bisphenol A (BpA), an endocrine-disrupting chemical. The biosensor is based on an SPR sensor platform (SPRCD) and the binding inhibition detection format. The detection of BpA in PBS and wastewater was performed at concentrations ranging from 0.05 to 1,000 ng/ml. The limit of detection for BpA in PBS and wastewater was estimated to be 0.08 and 0.14 ng/ml, respectively. It was also demonstrated that the biosensor can be regenerated for repeated use. Results achieved with the SPR biosensor are compared with those obtained using ELISA and HPLC methods.

• MeSH
• benzhydrylové sloučeniny MeSH
• biosenzitivní techniky metody   MeSH
• chemické látky znečišťující vodu analýza   chemie   MeSH
• fenoly analýza   chemie   MeSH
• limita detekce MeSH
• povrchová plasmonová rezonance metody   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• benzhydrylové sloučeniny MeSH
• bisphenol A MeSH Prohlížeč
• chemické látky znečišťující vodu MeSH
• fenoly MeSH

Diabetes mellitus represents one of the most widespread diseases in civilization nowadays. Since the costs for treating and diagnosing of diabetes represent several billions of dollars per year, a cheap, fast, and simple sensor for diabetes diagnosis is needed. Electrochemical insulin sensors can be considered as a novel approach for diabetes diagnosis. In this study, carbon electrode with electrodeposited NiO nanoparticles was selected as a suitable electrode material for insulin determination. The morphology and surface composition were studied by scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy, and X-ray photoelectron spectroscopy (XPS). For a better understanding of insulin determination on NiO-modified electrodes, the mechanism of electrochemical reaction and the kinetic parameters were studied. They were calculated from both voltammetric and amperometric measurements. The modified carbon electrode displayed a wide linear range from 600 nM to 10 µM, a low limit of detection of 19.6 nM, and a high sensitivity of 7.06 µA/µM. The electrodes were stable for 30 cycles and were able to detect insulin even in bovine blood serum. Additionally, the temperature stability of this electrode and its storage conditions were studied with appropriate outcomes. The above results show the high promise of this electrode for detecting insulin in clinical samples.

• Klíčová slova
• NiO nanoparticles, electrochemical sensor, insulin,
• MeSH
• elektrochemické techniky * MeSH
• elektrody MeSH
• inzulin MeSH
• lidé MeSH
• limita detekce MeSH
• nanočástice * MeSH
• nikl MeSH
• skot MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• skot MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• inzulin MeSH
• nikl MeSH

A new HPLC method was developed and validated for the determination of asymmetric and symmetric dimethylarginines and l-arginine in human plasma. After SPE and evaporation of the eluate, the samples were derivatised with an o-phthaldialdehyde reagent containing 3-mercaptopropionic acid. The derivatives formed were analysed by isocratic RP-HPLC with electrochemical detection at +320 mV. The mobile phase consisted of 50 mM phosphate buffer (pH 6.1) containing 10% v/v acetonitrile, the flow rate was 1 mL/min. The retention times of all compounds including monomethylarginine (internal standard) were <24 min. The LODs (S/N 3:1) were 0.012 μM for both dimethylarginines and 0.013 μM for L-arginine; the linearity of the method was from 0.1 to 20 μM for both dimethylarginines and from 1 to 200 μM for L-arginine. Absolute extraction recoveries measured for all analytes ranged from 85 to 88%.

• Klíčová slova
• Arginine, Asymmetric dimethylarginine, Electrochemical detection, HPLC, Symmetric dimethylarginine,
• MeSH
• arginin analogy a deriváty   krev   MeSH
• biochemická analýza krve přístrojové vybavení   metody   MeSH
• elektrochemické techniky * MeSH
• lidé MeSH
• limita detekce MeSH
• referenční standardy MeSH
• vysokoúčinná kapalinová chromatografie * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• validační studie MeSH
• Názvy látek
• arginin MeSH
• dimethylarginine MeSH Prohlížeč

Conductivity detection is a universal detection technique often encountered in electrophoretic separation systems, especially in modern chip-electrophoresis based devices. On the other hand, it is sparsely combined with another contemporary trend of enhancing limits of detection by means of various preconcentration strategies. This can be attributed to the fact that a preconcentration experimental setup usually brings about disturbances in a conductivity baseline. Sweeping with a neutral sweeping agent seems a good candidate for overcoming this problem. A neutral sweeping agent does not hinder the conductivity detection while a charged analyte may preconcentrate on its boundary due to a decrease in its effective mobility. This study investigates such sweeping systems theoretically, by means of computer simulations, and experimentally. A formula is provided for the reliable estimation of the preconcentration factor. Additionally, it is demonstrated that the conductivity signal can significantly benefit from slowing down the analyte and thus the overall signal enhancement can easily overweight amplification caused solely by the sweeping process. The overall enhancement factor can be deduced a priori from the linearized theory of electrophoresis implemented in the PeakMaster freeware. Sweeping by neutral cyclodextrin is demonstrated on an amplification of a conductivity signal of flurbiprofen in a real drug sample. Finally, a possible formation of unexpected system peaks in systems with a neutral sweeping agent is revealed by the computer simulation and confirmed experimentally.

• Klíčová slova
• Affinity capillary electrophoresis, Complexation, Conductivity detection, Online preconcentration, Sweeping,
• MeSH
• analgetika MeSH
• cyklodextriny chemie   MeSH
• elektrická vodivost * MeSH
• elektroforéza kapilární metody   MeSH
• flurbiprofen chemie   MeSH
• limita detekce MeSH
• počítačová simulace MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• analgetika MeSH
• cyklodextriny MeSH
• flurbiprofen MeSH

In this article, optimization of BGE for simultaneous separation of inorganic ions, organic acids, and glutathione using dual C4 D-LIF detection in capillary electrophoresis is presented. The optimized BGE consisted of 30 mM 2-[4-(2-hydroxyethyl)piperazin-1-yl]ethanesulfonic acid, 15 mM 2-amino-2-hydroxymethyl-propane-1,3-diol, and 2 mM 18-crown-6 at pH 7.2 and allowed simultaneous separation of ten inorganic anions and cations, three organic acids and glutathione in 20 min. The samples were injected hydrodynamically from both capillary ends using the double-opposite end injection principle. Sensitive detection of anions, cations, and organic acids with micromolar LODs using C4 D and simultaneously glutathione with nanomolar LODs using LIF was achieved in a single run. The developed BGE may be useful in analyses of biological samples containing analytes with differing concentrations of several orders of magnitude that is not possible with single detection mode.

• Klíčová slova
• Capillary electrophoresis, Contactless conductivity detection, Dual detection, Laser induced fluorescence detection, Saliva,
• MeSH
• dechové testy metody   MeSH
• design vybavení MeSH
• elektrická vodivost MeSH
• elektroforéza kapilární metody   MeSH
• fluorescenční spektrometrie metody   MeSH
• glutathion analýza   izolace a purifikace   MeSH
• ionty analýza   izolace a purifikace   MeSH
• kyseliny karboxylové analýza   izolace a purifikace   MeSH
• lidé MeSH
• limita detekce MeSH
• lineární modely MeSH
• reprodukovatelnost výsledků MeSH
• slzy chemie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• glutathion MeSH
• ionty MeSH
• kyseliny karboxylové MeSH