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2-pyridyl thiourea and methyl-2-pyridyl ketoxime based perrhenate, Re(VII), UV–vis spectrophotometric methods were evaluated in nitrate and bicarbonate solutions ranging from 0.001M to 0.5M. Standard curves at [Re]=2.5–50mgL−1 for the Re(IV)-thiourea and the Re ketoxime complexes were constructed at 405nm and 490nm, respectively. Detection of limits for N-(2-pyridyl) thiourea and methyl-2-pyridyl...
In this work, we report a novel microfluidic gas collecting platform aiming at simultaneous sample extraction and multiplex mass spectrometry (MS) analysis. An alveolar-mimicking elastic polydimethylsiloxane (PDMS) structures was designed to move dynamically driven by external pressure. The movement was well tuned both by its amplitude and rhythm following the natural process of human respiration...
A series of glucose bioelectrodes were prepared by glucose oxidase (GOx) immobilization into laponite hydrogel films containing DNA bioinspired polycations made of vinylbenzyl thymine (VBT) and vinylbenzyl triethylammonium chloride (VBA) with general formulae [(VBT)m(VBA)n]≈25n+ with m=0, 1 and n=2, 4, 8, deposited onto glassy carbon electrode. The bioelectrodes were characterized by chronoamperometry,...
The growing global demand for specialty coffee increases the need for improved coffee quality assessment methods. Green bean coffee quality analysis is usually carried out by physical (e.g. black beans, immature beans) and cup quality (e.g. acidity, flavour) evaluation. However, these evaluation methods are subjective, costly, time consuming, require sample preparation and may end up in poor grading...
Major threats in metabolomics clinical research are biases in sampling and preparation of biological samples. Bias in sample collection is a frequently forgotten aspect responsible for uncontrolled errors in metabolomics analysis. There is a great diversity of blood collection tubes for sampling serum or plasma, which are widely used in metabolomics analysis. Most of the existing studies dealing with...
In this work, we presented a simple, label-free and rapid-responsive fluorescence assay for iodide (I−) detection based on “molecular beacon (MB)”-hosted thioflavin T (ThT), achieving a limit of detection as low as 158nM. The proposed method exhibited very good selectivity to I− ions over other anions interference due to the strong binding force between I− ions with Hg2+. Upon the addition of I− ions,...
Dimethyl sulphide (DMS) is an important compound in global atmospheric chemistry and climate change. Traceable international standards are essential for measuring accurately the long-term global trend in ambient DMS. However, developing accurate gas standards for sub-nanomole per mole (nmol/mol) mole fractions of DMS in a cylinder is challenging, because DMS is reactive and unstable. In this study,...
The aim of this work is to develop a nanoparticle-based methodology to find out biomarkers of diagnostic for knee osteoarthritis, KOA, through the use of matrix assisted laser desorption ionization time-of-flight-based mass spectrometry profiling.Urine samples used for this study were obtained from KOA patients (42 patients), patients with prosthesis (58 patients), and controls (36 individuals) with...
A flow potentiometric method for determination of caffeine in saliva is suggested. This task is important for non-invasive assessment of drug metabolizing system activity in hepatocytes. In the current study, stepwise injection analysis (SWIA) was successfully combined with single-drop liquid microextraction (SDLME) and solvent exchange procedure. The method is based on the caffeine SDLME with subsequent...
This study combined a molecularly-imprinted polymer with headspace solid-phase microextraction (HS-SPME). Preparation of molecularly-imprinted polymer is not effective for volatile compounds. To overcome this limitation, pyrrole was chosen as a template for the preparation of the furan-imprinted polymer. The holes in the synthesized polymer were suitable for furan adsorption because the chemical structure...
Herewith the development of a rapid and powerful LC methodology (with three different detectors) is presented to determine triterpenic acids and dialcohols in extracts from Olea europaea tissues (olive skin, pulp and leaves). After the proper optimization of the LC, DAD and MS conditions and the comprehensive characterization of the behavior of each analyte in ESI and APCI (with accurate m/z signals...
This work presented the design, syntheses and photophysical properties of a rhodamine B-based fluorescence probe, which exhibited a sensitive and selective recognition towards mercury (II). The chemosensor RA (Rhodamine- amide- derivative) contained a 5-aminoisophthalic acid diethyl ester and a rhodamine group, and the property of spirolactone of this chemosensor RA was detected by X-ray crystal structure...
A fluorescent immunochromatographic strip test (ICST) based on the use of Quantum Dots (QD) was developed and applied to detect fumonisins in maize samples. A limit of detection for fumonisin B1 of 2.8µgL−1 was achieved, with an analytical working range of 3–350µgL−1, corresponding to 30–3500µgkg−1 in maize flour samples, according with the extraction procedure. The time required to perform the analysis...
TEV protease is of great importance for in vitro and in vivo site-specific cleavage of proteins. The proteolytic efficiency of TEV protease is often regulated by mutation of the substrate, which is irreversible and hard to be modulated. Herein, a facile and reversible method, based on phosphorylation in the substrate, is developed to regulate the cleavage capability of TEV protease. Phosphorylation...
Xenobiotic exposure during pregnancy is inevitable. Determination of perfluorinated compounds (PFCs), chemicals described as environmental contaminants by Public Health Authorities due to their persistence, bioaccumulation and toxicity, is a challenge. In the present work, a method based on a simplified sample treatment involving freeze–drying, solvent extraction and dispersive clean-up of the extracts...
2-aminothiazoline-4-carboxylic acid (ATCA) is a hydrogen cyanide metabolite that has been found to be a reliable biomarker of cyanide poisoning, because of its long-term stability in biological material. There are several methods of ATCA determination; however, they are restricted to extraction on mixed mode cation exchange sorbents. To date, there has been no reliable method of ATCA determination...
Lichens are symbiotic organisms known for producing unique secondary metabolites with attractive cosmetic and pharmacological properties. In this paper, we investigated three standard methods of preparation of Pseudevernia furfuracea (blender grinding, ball milling, pestle and mortar). The materials obtained were characterized by electronic microscopy, nitrogen adsorption and compared from the point...
The main objective of this study was to develop a novel surface plasmon resonance (SPR) nanosensor method based on a more rapid and selective determination of erythromycin (ERY) in the aqueous solution. This study is a combination of three techniques, which are miniemulsion polymerization, molecular imprinting and surface plasmon resonance techniques. In the first part, nanoparticles prepared with...
Polyaniline/graphene quantum dots (PANI/GQDs) were used to modify a screen-printed carbon electrode (SPCE) in a flow-based system. A method for rapidly determining the Cr(VI) concentrations by using stopped-flow analysis has been developed using an Auto-Pret system coupled with linear-sweep voltammetry using the PANI/GQD-modified SPCE. The GQDs, synthesized in a botton-up manner from citric acid,...
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