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Sulfur, nitrogen co-doped carbon dots (S, N co-doped C-dots) as highly selective fluorescent probe for uric acid (UA) detection were designed. The S, N co-doped C-dots with high quantum yield of 73.1% were prepared by hydrothermal method. It was found that the fluorescence of S, N co-doped C-dots was quenched apparently by hydroxyl radicals from Fenton reaction between H2O2 and Fe2+. The production...
An ultra-sensitive electrochemical biosensor was successfully developed for rapid detection of pirimiphos-methyl in olive oil, based of genetically-engineered acetylcholinesterase (AChE) immobilization into electrospun chitosan/poly (vinyl alcohol) blend nanofibers. Due to their unique properties such as spatial structure, high porosity, and large surface area, the use of nanofibers allowed improving...
We evaluated the impact of urban air pollution on egg yolk tempera paint dosimeters (binary mixture samples made with historic artist´s blue, red and white pigments) by tracking changes over time in their lipid matrix-assisted laser desorption ionization time-of-flight mass spectra (MALDI-TOF-MS) profiles. We studied triacylglycerols (TGs), phospholipids (PLs) and their oxidation by-products from...
Chemically modified carbon-paste (CMCP) and membrane- sensors based on incorporating benzothonium-tetraphenylborate (BT-TPB) were constructed for the analysis of benzethonium chloride, and some other surfactants such as sodium lauryl ether sulphate (SLES), sodium dodecyl sulphate (SDS), and linear alkylbenzene sulphonic acid (LABSA). All sensors showed good sensitivity and reverse wide linearity over...
The influence of the experimental variability (instrumental repeatability, instrumental intermediate precision and sample preparation variability) and data pre-processing (normalization, peak alignment, background subtraction) on the discrimination power of multivariate data analysis methods (Principal Component Analysis -PCA- and Cluster Analysis -CA-) as well as a new algorithm based on linear regression...
A simple and rapid HPLC method using 2-chloro-1-methyllepidinium tetrafluoroborate (CMLT) as a derivatization reagent was developed for simultaneous determination of homocysteine (Hcy), glutathione (GSH), γ-glutamylcysteine (γ-GluCys), cysteinylglycine (CysGly), N-acetylcysteine (NACys) and cysteine (Cys) in human saliva, plasma and urine. Separation of the analytes was achieved in just 7min using...
Ionic liquids (ILs) are one of the very promising media for the passive sampling of organic contaminants in water. These compounds offer a wide range of interactions with various analytes and give possibilities to control analyte properties by altering their structures, but most of all, possess a high polarity independent of the water solubility. Recently, some ILs were successfully applied as the...
A facile one-pot strategy has been developed for the aqueous synthesis of Gd doped CdTe (Gd:CdTe) QDs as fluorescence and magnetic resonance imaging dual-modal agent. The prepared Gd:CdTe QDs showed narrow size distribution and the average size was less than 5nm. The amount of Gd3+ dopant in Gd:CdTe QDs significantly affected the optical properties of obtained QDs. The highest PL QY for the prepared...
A new near-infrared (NIR) spectroscopic method was developed for the analytical measurement of lipid oxidation in sunflower kernel paste (tahini), which was chosen as an example of a complex oilseed-based food product. The NIR spectra of sunflower tahini were acquired for the extracted fat phase (EFP) and for the intact sunflower tahini (IST) samples during controlled storage. The best peroxide value...
A new method for the determination of major metal elements in high salinity brines was developed by solution cathode glow discharge (SCGD) with flow injection analysis (FIA). The matrix interferences of major cations and anions in brines have been evaluated. It was found that high concentration of Na+ and K+ could interfere each other, K+ at a concentration of 400mgL−1 enhanced the signal intensity...
The paper presents a combined technique of germanium dioxide analysis by inductively coupled plasma atomic emission spectrometry (ICP-AES) with preconcentration of trace elements by distilling off matrix and electrothermal (ETV) introduction of the trace elements concentrate into the ICP. Evaluation of metrological characteristics of the developed technique of high-purity germanium dioxide analysis...
A novel signal amplification strategy based on Cu2+-dependent DNAzyme was developed for sensing Cu2+ ion by combining hybridization chain reaction (HCR) with fluorescence resonance energy transfer (FRET) technique. In the presence of Cu2+ ion, the substrate strands of Cu2+-dependent DNAzyme immobilized on magnetic beads were specifically cleaved and released. The released strands initiated the HCR...
A new ultrasonic-thermostatic-assisted cloud point extraction procedure (UTA-CPE) was developed for preconcentration at the trace levels of vanadium (V) and molybdenum (Mo) in milk, vegetables and foodstuffs prior to determination via flame atomic absorption spectrometry (FAAS). The method is based on the ion-association of stable anionic oxalate complexes of V(V) and Mo(VI) with [9-(diethylamino)benzo[a]phenoxazin-5-ylidene]azanium;...
Many intriguing physical and chemical processes commonly take place at the solid/liquid interface. Total internal reflection illumination, together with single molecule spectroscopy, provides a robust platform for the selective exploration of kinetic processes close the interface. With these techniques, it was observed that the distribution of Rhodamine B molecules close to a solid/liquid interface...
In the Near-infrared (NIR) spectral measurement it is not always possible to keep the experimental conditions constant. The fluctuations in external variables, such as temperature, will result in a nonlinear shift and a broadening of the spectral bands. In this study, the temperature-induced spectral variation coefficient (TSVC) was obtained by using loading space standardization (LSS). The relationship...
The aim of this work was to study the feasibility of producing an egg matrix candidate reference material for salinomycin. Preservation techniques investigated were freeze-drying and spray drying dehydration. Homogeneity and stability studies of the produced batches were conducted according to ISO Guides 34 and 35. The results showed that all produced batches were homogeneous and both freeze-drying...
In this work, a non-commercial triaxial geometry energy dispersive X-ray Fluorescence (EDXRF) setup and a benchtop µ-XRF system were used to identify postmortem contamination in buried bones. For two of the individuals, unusually high concentrations of Cu and Pb, but also Zn (in one individual) were observed. The pigments of the burial shroud coverings have been identified as the source of contamination...
This study provides accurate near infrared (NIR) spectroscopic models on some laboratory determined clinicochemical parameters (i.e. total lipid (5.57±1.95 g/l), triglyceride (2.59±1.36 mmol/l), total cholesterol (3.81±0.68 mmol/l), high density lipoprotein (HDL) cholesterol (2.45±0.58 mmol/l)) of blood serum samples of fattened geese. To increase the performance of multivariate chemometrics, samples...
Fatty acid alkyl esters (FAAEs) were determined at 10–100mg/L in biodiesel and blends with petrodiesel without sample pre-treatment using gas chromatography with a tandem differential mobility detector. Selectivity was provided through chromatographic separations and atmospheric pressure chemical ionization reactions in the detector with mobility characterization of gas ions. Limits of detection were...
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