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Abstract We 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

Abstract We 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

Abstract A 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

Abstract This 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

Abstract The 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

Abstract A 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

Abstract An 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

Abstract New 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

Abstract This 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)

Abstract Specific 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

Abstract The 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

Abstract We 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

Abstract To 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

Abstract A 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

Abstract In 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

Abstract A 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

Abstract Diffuse 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

Abstract A 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

Abstract A 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

Abstract The 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

Abstract We 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

Abstract The 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

Abstract A 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

Abstract A 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

Abstract Determination of volatile organic compounds (VOCs), the metabolites produced in human body, contributes to better understanding of the mechanisms responsible for the progression of diseases and facilitates monitoring of the responses to treatment. Urine samples are a rich source of VOCs and they constitute a non-invasive tool for diagnosis of various metabolic and pathological states. The

Abstract The novel approach of cloud point extraction in the presence of multi-walled carbon nanotubes (CPE/MWCNTs) is presented for removal of Direct Green 26 (DG26) from aqueous solutions. The experiments were conducted based on the Box-Behnken experimental design and the removal process was optimized by the response surface modeling and desirability function (DF) approach. Effects of the experimental

Abstract Techniques for the determination of the elemental composition of dietary supplements (Multifort®, Komplivit®) are presented. It is proposed to use a state-of-the-art analytical method, total reflection X-ray fluorescence spectrometry. The differences in the sample preparation of encapsulated and not encapsulated dietary supplements are described. The effect of encapsulation on the results

Abstract A procedure is developed for determining trace amounts of Pt, Pd, Rh, Ru, Ir, and Au in ultrabasic rocks by inductively coupled plasma mass spectrometry. Chemical sample preparation included acid decomposition, separation of the main matrix components on an AG-X8 cation exchanger, and the subsequent separation of Zr, Hf, and Ta on an LN-Rezin complexing adsorbent. The limits of detection for

Abstract Sensors for the potentiometric determination of mefenamic and phenylanthranylic acids are prepared on the basis of single- and the double-layer plasticized polyvinylchloride membranes. Ion pairs of perchlorate and mefenamic and phenylanthranylic acid with basic fuchsin are synthesized for the fabrication of membranes. The composition of compounds is confirmed by spectrophotometry and IR spectrometry

Abstract It was shown that the differential spectrophotometric method for the determination of monomeric anthocyanins (in a mixture with polymeric ones) is unsuitable for measurements of anthocyanins acylated by substituted cinnamic acids. This is explained by a competition between the reaction of the nucleophilic addition of a water molecule (with the release of H+) to flavylium ions with the formation

Abstract Conditions for the extraction of a phosphonylated nonapeptide, phosphonylated tyrosine, and cyclohexylmethylphosphonic acid from human blood plasma followed by HPLC determination with detection by high-resolution tandem mass spectrometry were optimized. Conditions for human blood plasma sample preparation, mass-spectrometric detection in selected reaction monitoring mode, and gradient elution

Abstract This work illustrates four different spectrophotometric methods for metformin (MET) and canagliflozin (CANA) quantification in their recently approved pharmaceutical with trade name Invokamet®. The proposed methods are simple, definitive and accurate. Certain ensuing steps implementing zero spectra and/or ratio and/or derivative spectra were applied. Via implementing spectrum subtraction method

Abstract An increase in the steric accessibility of a quaternary ammonium salt (QAS) exchange center leads to a significant increase in the exchange constant for most of the studied doubly charged anions (sulfate, sulfite, molybdate, tungstate, hydrogen phosphate, and selenate), which reaches for “pure” anion-exchange systems of more than five orders of magnitude. The effect of minimizing of an anion-exchange

Abstract We present a method for the quantitative determination of the Agidol-1 antioxidant additive in fuels for jet engines in concentrations of 0.001–0.006 wt % by HPLC after its preconcentration by extraction with methanol. The ratio of fuel-to-methanol-to-water in extraction is optimized. Chromatographic separation was performed on a Kromasil C18 reversed-phase column, upon isocratic elution with

Abstract Increasing application of pesticides and their toxicity made it essential to develop reliable and accurate methods of their trace quantification. This research was aimed to develop an electrochemical nanocomposite sensor based on molecularly imprinted polymer (MIP) for selective and sensitive determination of carbofuran. The proposed sensor was made based on incorporation of carbofuran MIP

Abstract In the present study, an electroanalytical method for the determination of hesperidin using adsorptive stripping voltammetry at an unmodified boron-doped diamond (BDD) electrode is presented. In cyclic voltammetry, the compound showed one irreversible and adsorption-controlled oxidation peak, resulting in the formation of a couple with a reduction and re-oxidation wave at less positive potentials

Abstract The extraction of polyphenol component of arctic brown algae of the Fucus vesiculosus type and the subsequent fractionation of the extract by column chromatography on a Sephadex LH-20 adsorbent are carried out. The obtained fractions are characterized by size-exclusion chromatography, HPLC with UV and mass spectrometric detection (HPLC–UV-MS), and matrix-assisted laser desorption/ionization

Abstract A simple and rapid online hydride generation technique based on ultrasonic nebulizer was applied for the first time for the simultaneous determination of trace amounts of As, Bi, Sb, Se and Te by inductively coupled plasma optical emission spectrometry. In this method, we used an ultrasonic nebulizer as a hydride generator and sample introducer simultaneously. An ultrasonic nebulizer was applied

Abstract In the present study, an immunosorbent surface-based theophylline determination method was developed and validated. The procedure was tested on milk samples. Theophylline was removed from milk by an immunosorbent surface. The efficiency of theophylline removal was found to be between 95–97%. The proposed method is cost effective and does not require any special equipment. Detection and quantification

Abstract The values of the relative polarity and hydrophobicity of the main classes of acyl-containing glycerolipids are calculated. These values, obtained using standard values of the elution strength of solvents (from n-hexane to water), can belong to scales of relative polarity and hydrophobicity, including a variety of organic compounds of natural origin. It is proposed to use n-hexadecane and

Abstract Electrochemical properties of regorafenib (REG) were studied in 0.1 M Britton−Robinson buffer-methanol solutions (3 : 2, v/v) with pH between 3 and 8 at carbon paste electrode by cyclic and differential pulse voltammetry. The results exhibited irreversible anodic peak at about 0.90 V vs. Ag/AgCl, NaCl (3 M). The anodic peak was found to be diffusion–adsorption controlled. Mechanism of REG

Abstract A possibility of the separation of trace amounts of arsenic and antimony and macroquantities iron, chromium, molybdenum, and tungsten by the precipitation of the latter was investigated; regularities of the coprecipitation of arsenic and antimony are studied. The coprecipitation of arsenic and antimony in the precipitation of iron, chromium, molybdenum, and tungsten can be inhibited by introducing

Abstract We developed and tested a high-performance system for the acid mineralization of silicate samples in open vessels of original design with programmable heat treatment conditions. A formalized description of operations in the procedures of the acid mineralization of various silicate samples (ultrabasic, basic, and acidic) is proposed, both on a quantitative and a descriptive level. Problems

Abstract The review covers modern directions of the implementation of high-resolution continuous-source electrothermal atomic absorption spectrometry (HR CS ETAAS) for quantitative analysis. Approaches to the direct analysis of solid samples of various compositions, including determination using aqueous reference solutions, analysis of suspensions and sorbates after sorption separation, use of various

Abstract A simple, fast and efficient method based on ultrasound-assisted emulsification microextraction (USAEME) followed by HPLC has been developed for simultaneous determination of Carbamazepine (CBZ) and Lamotrigine (LTG) in biological samples. The influence of different parameters affecting the USAEME procedure was evaluated to optimize the efficiency of the process. At these conditions, validation

Abstract The anion-exchange extraction of thiocyanate ions by various quaternary ammonium salts was studied. Exchange constants of thiocyanate ions for the chloride ion \(\left( {\log K_{{{\text{C}}{{{\text{l}}}^{ - }}}}^{{{\text{SC}}{{{\text{N}}}^{ - }}}}} \right)\) were determined. Thus, in the transition from 3,4,5-tris(dodecyloxy)benzyltrimethylammonium bromide to 3,4,5-tris(dodecyloxy)benzyltrilaurylammonium

Abstract The selection and application of an array of piezoelectric sensors for assessing the state of respiratory organs in calves by the composition of the headspace of the exhaled condensate are discussed. We considered the relationship between the output recorded data, calculated data of the sensor array, and the state of the respiratory system of an animal, determined by the results of clinical

Abstract A combined method of analysis of high-purity germanium dioxide by atomic emission spectrometry with matrix preseparation and trace element preconcentration was developed. The matrix was separated in an autoclave of a MARS 5 microwave system without the contact of samples with an acid solution. The method allows the determination of the following 50 analytes with the limits of detection 10–8–10–5

Abstract A voltammetric method for evaluating polyphenol–protein interactions was developed based on the oxidation of polyphenols at an electrode modified with multi-walled carbon nanotubes and electropolymerized quercetin. Tea polyphenols (catechin and epigallocatechin gallate) and milk proteins (casein, bovine serum albumin, and β-lactoglobulin) were considered as model systems. It was found that

Abstract We studied the main electrode functions of carbon paste electrodes (CPEs) modified with 0–20% of dithiooxamidated polysiloxane with respect to palladium(II). The conditions for the potentiometric titration of palladium(II) using modified CPEs as indicator electrodes were selected, namely, pH 1–2, solutions of EDTA and potassium iodide as the titrants; and modifier concentration is 0, 5, and

Abstract A method of chromatography–mass spectrometry is used to study the impurity composition of arsine synthesized by the reaction of arsenic chloride with sodium borohydride. Capillary adsorption columns with adsorbents modified silica and polytrimethylsilylpropine is used for the separation of impurities. Impurities are identified by comparing their mass spectra with the NIST database, published

Abstract Two validated, accurate and selective chemometric models were developed to detect cyclobenzaprine·HCl (CZ) in the presence of its two major degradation products: dibenzocycloheptatrienone and anthraquinone. Additionally, a comparative study was conducted between two chemometric models, namely partial least squares regression (PLSR) and spectral residual augmented classical least squares (SRACLS)

Abstract The effect of matrix elements (Na, In, Bi, Zn, Cu) and nitric and hydrochloric acids on the analytical signals of impurity elements in nitrogen microwave-plasma atomic emission spectrometry (MP AES) was studied. In the range of acid concentrations 0.1–0.5 M (for rare-earth elements, 0.1–0.9 M), the analytical signals of the elements did not change. The presence of a matrix element in a concentration