AbstractThe adsorption and complexing properties of modified adsorbents based on a maleic anhydride–styrene copolymer with respect to thorium(IV) ions were studied. Adsorbents containing fragments of 2‑amino-4-chloro-6-sulfophenol and 2,4-diamino-6-phenyltriazine-1,3,5 are used. The main quantitative characteristics of the adsorption of thorium are determined, and the optimal adsorption conditions

AbstractAn atomization and excitation source for the analysis of solutions by atomic emission spectrometry is proposed on the basis of pulsed glow discharge with a solid anode and discharge gap geometry varied within the discharge. A portable atomic emission spectrometer recording total emission spectrum from a single sample drop is developed in its basis.

AbstractThe effect of the pH of the medium, the volume ratio of the extractant to water on the efficiency of caffeine extraction with acetonitrile from aqueous solutions by extractive freezing-out in a centrifugal force field is studied. The results can be explained in terms of the previously proposed theoretical process model. The highest recovery of caffeine was achieved at pH 6–7. The limit of determination

AbstractThe electrochemical behavior and determination of fentanyl as a strong analgesic drug was studied at the surface of glassy carbon electrode (GCE) modified by multi-walled carbon nanotubes (MWCNTs). The electrochemical determination of fentanyl was accomplished by differential pulse adsorptive stripping voltammetry after preconcentration under open circuit potential. The distribution of adsorbed

AbstractA simple method was developed for determining aloin in A. vera samples by UV–visible spectroscopy with the study of the results of measurements by principal component analysis (PCA), which showed the separation of samples in the PC space depending on their manufacturer. The spectra of model binary (aloin–malic acid) and ternary (aloin–malic acid–citric acid) systems and the spectra of A. vera

AbstractAfter optimization of fabrication conditions, the capacitively coupled plasma-treated polyimide (PI) substrates were coated with composites of molecularly imprinted polymers and CdTe quantum dots and used to detect tetracycline (Tc) in the range of 5–3000 μM (R2 = 0.9995) with a LOD of 0.2 μM (S/N = 3, RSD = 2.2% at 5 μM Tc, n = 10) by using a fluorescent quenching effect. The selectivity of

AbstractWe used conducting redox-active polymers based on chitosan and bovine serum albumin (BSA), covalently bound to mediators ferrocene or Neutral Red, or thionine, modified by carbon nanotubes, as a base of an amperometric biosensor for determining glucose. The structure of the obtained polymers was studied by IR spectroscopy and scanning electron microscopy. Their electrochemical characteristics

AbstractA novel sample pre-treatment technique based on vortex and ultrasound-assisted surfactant-enhanced emulsification microextraction followed by gas chromatographic–mass spectrometric detection has been developed to determine the selected pesticide residues in honey samples. The key parameters which have affected extraction efficiency were investigated and optimized. Under optimal conditions,

AbstractThe study and analysis of dust nano- and microparticles are necessary in the estimation of anthropogenic load on the environment and the determination of the sources of pollution in urban ecosystems. In this work, an approach based on a multistage membrane filtration method is proposed for assessing the contribution of a metallurgical enterprise to the pollution of nano- and microparticles

AbstractIn the present study a high performance liquid chromatographic–mass spectrometric (LC–MS) method was developed for the measurement of ascorbic acid in human plasma and white blood cells. Special attention was paid to the known difficulties of ascorbic acid stability, and a plasma sample preparation method was developed, accordingly. The novel objective of this work was to focus on the determination

AbstractIt was found that nickel particles electrodeposited on the surface of planar carbon electrodes (PE; Ni–PE) exhibit catalytic activity in the electrooxidation of glucose, insulin, and cholesterol (CS) in alkaline media, and cobalt particles (Co–PE), in the oxidation of CS, insulin, and uric acid (UA) in neutral media. In recording an analytical signal in a system of sequential-injection analysis

AbstractThe conditions of the sorption concentration of o-xylene and polynuclear aromatic hydrocarbons (PAHs) on hypercrosslinked polystyrene in the dynamic mode are developed. A procedure is proposed for the determination of o-xylene and PAHs in thawed snow, based on the sorption preconcentration of these compounds and their further determination by gas chromatography–mass spectrometry. Samples of

AbstractA micelle mediated separation and preconcentration method for flame atomic absorption spectrophotometric (FAAS) determination of Cu was developed. The method is based on complex formation between Cu and 1-(2-pyridylazo)-2-naphthol and cloud point extraction with Tergitol NP-7 surfactant prior to FAAS determination. The parameters affecting quantitative extraction of copper, including pH, surfactant

AbstractA novel molecularly imprinted solid–phase extraction method was developed coupled with HPLC for ceftazidime determination in biological fluids. Various parameters such as molecular recognition properties, adsorption capacity and selectivity of the molecularly imprinted polymer (MIP) were evaluated. The optimal conditions for solid-phase extraction consisted of conditioning with 5 mL of methanol

AbstractA version of an oxythermograph based on the use of air oxygen as an oxidant is used for the determination of the total of poorly volatile compounds in gasolines. This allowed the elaboration of a rapid eco-friendly reagentless method for the determination of resinous substances in gasolines, requiring no chemical reagents and the subsequent utilization of the reaction products.

AbstractWe reported a tin film CMK-3 modified carbon paste electrode (Sn–CMK-3/CPE), a brand new electrode combining the ordered mesoporous carbons (OMCs) and tin film to detect trace cadmium. As one of the OMCs, CMK-3 has the distinct advantage of conducting electrons quickly and good adsorptivity because the pores in it are regularly ordered and controllable with the pore diameters of about 3.8–4

AbstractWe developed procedures for the rapid screening and sensitive determination of residues of 19 β-lactam antibiotics in matrices of various food products (meat, kidneys, liver, bacon, milk, eggs, honey) using ultrahigh-performance liquid chromatography–high-resolution quadrupole time-of-flight mass spectrometry. Acetonitrile was used to precipitate proteins and extract analytes; the extract was

AbstractIn this study, a new magnetic ion-imprinted polymer was prepared as a nanosorbent for selective extraction and pre-concentration of low levels of Cd(II) and Ni(II) prior to determination by flame atomic absorption spectrometry. The sorbent material consists of graphene oxide as a carrier, Fe3O4 nanoparticles as magnetic components immobilized on the surface of the carrier and polydopamine as

AbstractWe developed an all-solid-state sensor for monoascorbate ion based on a composite containing copper(II) ions (5 wt %), graphite and epoxy resin. The sensor presented super-Nernstian response at room temperature under continuous bubbling of oxygen gas in sample. The detection limit of the sensor was 0.02 mM and its linear range was between 0.05 and 1.5 mM with upper limit of quantification equal

AbstractSemiconductor sensors based on gallium arsenide, modified by the electrochemical method, have been developed for the potentiometric titration of metal ions. After surface modification, the electroanalytical characteristics of GaAs electrodes are improved, namely, the slope of the electrode function increases, the linearity range of the electrode function widens, and the response time decreases

AbstractTerpenoids of medicinal plants are one of the most important sources of therapeutic drugs. Among them, Vincristine (VCR) is prescribed for a wide variety of cancer types. Therefore, development of sensitive methods for VCR determination is urgently required. Here, a label-free and highly sensitive impedimetric biosensor was fabricated for electrochemical detection of VCR. First, multi-wall

AbstractA convenient, cheap and accurate method for the determination of quisqualic acid in traditional Chinese medicine Quisqualis fructus by pre-column derivatization with 2-nitrobenzenesulfonyl chloride and HPLC was established. Quisqualis fructus samples were homogenised in water after being crushed and degreased with petroleum ether. Target compounds were separated and detected on a C18 column

We propose a procedure for the simultaneous determination of biomarkers of the action of sulfur mustard (SM, 2,2'-dichlorodiethyl sulfide), namely, a depurinized adduct with DNA (N7-hydroxyethylthioethyl guanine) and an adduct with acetylcysteine (ACC) (1,1'-sulfonylbis[2-S-(N-acetylcysteinyl)ethane]), in urine by high-resolution HPLC–tandem mass spectrometry with electrospray ionization. The limit

AbstractIn this paper, we evaluated the use of a silylation reagent N-methyl-N-(tert-butyldimethylsilyl)trifluoroacetamide in the microwave-assisted derivatization method to replace a traditional prolonged heating method for the determination of 12 amino acids. Several parameters, including the kind of extraction solvent, extraction time, microwave power and microwave time, were optimized. The experiment

AbstractWe proposed a method for the selective and highly sensitive amperometric determination of dopamine and adrenaline in the presence of ascorbic and uric acids in a flow-injection system. Screen-printed electrodes modified with palladium nanoparticles, exhibiting catalytic activity in the electrooxidation of catecholamines, were used as a detector. The difference between the oxidation peak potentials

AbstractA method is developed for determining Ca, Mg, Zr, Hf, V, La, Ce, and Y in heat-resistant nickel alloys (HNAs) by inductively coupled plasma atomic emission spectrometry. A scheme of the dissolution of tests of HNA samples of different brands in a microwave digestion system is proposed. Analytical lines of elements and of the internal standard, free from significant spectral suporpositions,

AbstractAcute renal failure caused by Lianbizhi® injection can be attributed to andrographolide sodium bisulphite (ASB) and its main related substance RS413. For the safety evaluation of ASB and RS413, the pharmacokinetics of both compounds in rats was investigated through a liquid chromatography-tandem mass spectrometry method. After a simple protein precipitation with methanol, ASB and RS413 with

AbstractA procedure for the batch-injection amperometric determination of caffeine and theophylline using a screen-printed electrode modified with a composite based on ruthenium oxides and functionalized single-walled carbon nanotubes was developed. The effect of the parameters of the batch-injection system on the recorded signals was studied; the optimal detection conditions were selected. The analytical

AbstractSpecific features of using luminescent sensors with transducers based on a sensitive layer containing quantum dots immobilized in polymer matrixes of some fluorinated copolymers are described. Features of the formation of an analytical signal in time are studied. It is found that, in the analysis of some iodinated organic compounds, damped fluctuations of the luminescence intensity of the sensitive

AbstractHybrid materials based on perfluorinated sulfonic acid Nafion-type membranes and poly-3,4-ethylenedioxythiophene (PEDOT) with a gradient distribution of the latter along the film length were synthesized by in situ oxidative polymerization. The initial monomer concentration (0.01 and 0.002 M) and the concentration ratio of the monomer to the oxidant (1/1.25 and 1/2.5) were varied. We studied

AbstractSchisandrae chinensis fructus (Wuweizi) contains many triacylglycerols (TAGs). Therefore, it is inevitable that these TAGs will be part of Chinese medical preparations of Schisandrae chinensis fructus. It is important to identify TAGs in Schisandrae chinensis fructus. Fatty acids in Schisandrae chinensis fructus oil were identified by gas chromatography−mass spectrometry (GC−MS) after transesterification

AbstractThe problems and advantages of chromatographic methods for the determination of polycyclic aromatic hydrocarbons (PAHs) in model and real samples of black soil (chernozem), sand, and bottom sediments of the Sea of Azov and the Kurchansky estuary are discussed. We substantiated and implemented sample preparation for analysis using dispersion liquid–liquid microextraction. PAH concentrations

AbstractAn HPLC procedure was developed to determine twenty proteinogenic amino acids, ammonium, cystine, and alanyl-glutamine dipeptide in liquid culture media. 6-Aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) was used as a fluorescent label for the derivatization of amino acids with the subsequent HPLC separation on a reversed-phase column. Specificity, linearity, correctness, precision, analytical

AbstractA methodology is proposed for the highly selective, sensitive, and reliable determination of the total concentration of halogen and sulfur organic compounds in vegetable oils in the presence of inorganic salts, based on the direct high-temperature conversion of an oil sample in a stream of pure oxygen, absorption of inorganic salts in a reactor, absorption of the products of analyte conversion

AbstractIt is found that ionic liquids (ILs) based on imidazole can be used as extractants in the dispersive liquid–liquid microextraction of combined pesticide preparations (imidacloprid, biphenthrin, cypermethrin, malathion, phosalone, and diazinon) followed by their determination by HPLC with electrospray ionization tandem mass spectrometry detection with. The effect of the IL (1-hexyl-3-methylimidazolium

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AbstractWe show a possibility of the spectrophotometric determination of 2,4-dichlorophenoxyacetic acid based on the extraction of its ion pair (IP) with polymethine dye Astrafloxin FF with toluene. The maximum recovery of the ion pair from the aqueous phase is achieved at pH 6–11 and a dye concentration of (1.6–2.8) × 10–4 M. The conditional molar absorption coefficient of the ion pair is 4.0 × 104

AbstractWe developed a procedure for the gas-chromatographic determination of impurities in phosphorus oxychloride (POCl3) after the preliminary hydrolysis of the base and microextraction of impurities of organic and organochlorine substances with n-hexane. Impurities of chloroform, trichloroethylene, tetrachloroethylene, carbon tetrachloride, and benzene were identified. The degree of the microextraction

AbstractA colorimetric method based on digital image processing and an image capture device as a detector has been developed for determining methylene blue (MB) in human and veterinary dosage forms. Operational variables, such as capture devices, angle and modes of capture as well as measuring vessel geometry, were evaluated in order to establish the most suitable conditions to obtain accurate measurements

AbstractThis manuscript reports oxidation of amitriptyline at the carbon nanocomposite ionic liquid electrode fabricated using multi-walled carbon nanotubes and the ionic liquid 1-octylpyridinium hexafluorophosphate. The surface morphology of the electrode was characterized by scanning electron microscopy. Differential pulse voltammetry was applied as an analytical procedure for the determination of

AbstractThe challenge of the present work concerned in benznidazole assay in two drug delivery systems (DDS) which are different in the solubility character and sample complexity using HPLC−diode array detector (DAD) method. The lipid based DDS were mainly composed of medium-chain triglycerides and a mixture of surfactants, while the multicomponent inclusion complex systems involved cosolvents and

AbstractA combined use of comparator instrumental neutron activation analysis (INAA) including the internal standard method and energy-dispersive X-ray fluorescence spectrometry (EDXRF) for the determination of 14 rare-earth elements (REE) in geological samples at the level of their clarke concentrations is studied. A rapid analysis with the determination of light REE from La to Sm with Fe as an internal

AbstractAn adsorbent for HPLC, silica doubly layer-by-layer modified with 6,10-ionene and dextran sulfate, is obtained. The adsorbent has both hydrophobic and hydrophilic and ion-exchange properties (because of the presence of hydrophobic anions and cations on the surface). A possibility of using the obtained adsorbent in HPLC with tandem mass spectrometric detection is shown. The conditions for the

AbstractNew test systems made of nanofibers based on polyacrylonitrile and modified by NaOH are obtained for the chemisorption preconcentration of heavy metal (HM) ions and the subsequent colorimetric determination of their total amount . The kinetics of the adsorption of HM ions is studied, and corresponding adsorption isotherms are obtained. The adsorption capacities of nanofiber adsorbents for Mn2+

AbstractThis paper reports the application of a new type of material for matrices with high lipid content – zirconium based sorbent (Z-Sep+) which improves fat removal from the extracts for the simultaneous determination of polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticide (OCPs) residues in food of animal origin with gas chromatography−mass spectrometry (selected-ion monitoring)

AbstractSpecific features of the excitation of the X-ray fluorescence of fluorine in the presence of petrogenic elements are studied experimentally. The dependence of the intensity of the FKα-line on the atomic number of macroelements entering the composition of rocks is studied. It is found that the major contribution to the intensity of the FKα-line due to the effect of selective excitation is made

AbstractThe history of the appearance and development of selective androgen receptor modulators (SARMs) is described. The main classes of SARMs and various approaches to their determination are considered. The use of chromatography–mass spectrometry is shown to be promising for the reliable determination of SARM traces in various samples. Well-known sample preparation and determination methods in biological

AbstractWe developed a procedure for the high-precision determination of matrix elements of glasses of the Ga–Ge–As–Se system, including those doped with praseodymium, in the range of concentrations of gallium from 1 to 5 at %, germanium from 16 to 24 at %, arsenic from 14 to 18 at %, and selenium from 57 to 65 at %. A procedure for determining 0.05–0.5 wt % of praseodymium in these glasses by inductively

AbstractTo increase the accuracy of electron probe microanalysis, it was proposed to calculate absorption coefficients range-by-range, with selecting an optimum calculation method for each absorption range. The approach was implemented in the analysis of rock-forming minerals using the PAP correction method. Calculations of absorption coefficients in the region below the K-edge were performed using

AbstractA method is proposed for the determination of cysteine in an aqueous solution by its effect on the formation of gold nanoparticles on the surface of polyurethane foams. The method is based on the interaction of in situ formed gold nanoparticles with cysteine, which results in their stabilization in solution and in a decrease in the color intensity of the nanocomposite detected by diffuse reflectance

AbstractIn this research, different electrodes were made by combining certain percentages of carbon paste for a range of cations. Then, ligand selectivity was calculated for each cation using a potentiometric method to identify the most sensitive cation. A modified carbon paste electrode was applied to the quantification of chromium cation based on carbon nanotubes. In addition, paraffin, graphite

AbstractA liquid chromatography−mass spectrometry method was developed for the simultaneous quantitation of (2R,3R)-Dihydromyricetin and Myricetin in rat plasma samples to facilitate analysis of samples collected after administration of SenDeng-4 medicine. The plasma was subjected to protein precipitation with HCl (containing 10% ascorbic acid) and analyzed using electrospray ionization mass spectrometry

AbstractDiffuse reflectance spectroscopy was used to study the interaction of sodium diethyldithiocarbamate (DEDTC) with copper ions adsorbed on the disks of a PANF–KU-2 fibrous cation exchanger. The conditions for obtaining the substrate in the Cu-form are determined. The dependence of the analytical signal on the adsorption conditions of DEDTC was studied: the pH of the solution, the contact time

AbstractA molecularly imprinted polymer (MIP) of carbamazepine (CBZ) was synthesized so as to facilitate the selective extraction of CBZ from aqueous and bio-samples by using a non-covalent imprinting approach. Synthesized materials were characterized with Fourier-transform infrared spectroscopy and scanning electron microscopy studies. The imprinted polymer was evaluated and applied as a sorbent for

AbstractA chiral stationary phase is proposed on the basis of 3,4,9,10-perylenetetracarboxylic acid (3,4,9,10-perylentetracarbonacid, PTCA). The PTCA molecule itself is not chiral; however, it can form chiral supramolecular structures. Symmetry breaking during the self-assembly of PTCA supramolecular structures was carried out similarly to the Viedma ripening process. The obtained stationary phases

AbstractThe electroanalytical characteristics of an ion-selective electrode (ISE) with a membrane based on a supramolecular polymer composition containing polyvinyl chloride, o-nitrophenyl octyl ether plasticizer, tetradecyphosphonium pertechnetate ionophore, and a lipophilic additive of tetradecylphosphonium tetraphenyborate are studied. The limit of detection for the ISE in aqueous solutions containing

AbstractWe studied the extraction and preconcentration of phenol and its hydroxy derivatives using individual and mixed micelles of nonionic and cationic surfactants with the digital recording of the analytical signal. This approach is based on the color reaction of phenols with diazotized 4-nitroaniline and micellar extraction of the products of their interaction (azo compound). The micellar extraction

AbstractThe review is devoted to the application of time-of-flight secondary ion mass spectrometry (ToF–SIMS) to the analysis of biological tissues and cells. The invention of cluster primary ions significantly improved the sensitivity, especially in the mass range above several hundred of Daltons, which opened up the study of lipids, amino acids, nucleic acids, metabolites, and drugs. As other methods

AbstractA highly sensitive enzyme-induced metallization-based electrochemical signal amplification strategy was developed based on the integration of the enzyme-induced metallization reaction, Au nanoparticles (AuNPs)-induced silver deposition, chemically modified electrode and highly sensitive stripping voltammetry detection. The presence of alkaline phosphatase (ALP) catalyzed ascorbic acid 2-phosphate

AbstractA simple, economical and selective method employing ion pair dispersive liquid−liquid microextraction (DLLME) coupled with spectrophotometric determination of carbamazepine (CBZ) in pharmaceutical preparations and biological samples was developed. The method is based on reduction of Mo(VI) to Mo(V) using a combination of ammonium thiocyanate and ascorbic acid in acidic medium to form a red