Abstract Gas-phase on-line derivatization in the ion source of a DART mass spectrometer is a new approach to the efficient detection of alcohols in complex matrices. It does not require any special sample handling; it is based just on mixing an alcohol with a nitrogen-containing compound with high proton affinity. The resulting N-alkyl-derivatized cations appear in DART spectra as very characteristic

Abstract Axial aberration of the ion-optical system of a static mass analyzer is one of the factors limiting the transmittance and sensitivity of the device because of a need in significantly decreasing the vertical component of the ion beam emittance to get the required mass spectral resolution. We described an algorithm for selecting the optimal collimating system of the mass analyzer, which effectively

Abstract We obtained experimental surface ionization mass spectra of methenamine on the surface of intermetallic NaAu2 for the first time.

Abstract The present paper deals with the study of condensation reaction of aniline with acetone under electrospray ionization (ESI) conditions . An experimental setup is described for conducting reactions under ESI conditions with a possibility of the accumulation of reaction products. The aniline and acetone condensation products were analyzed by gas chromatography–mass spectrometry. Spraying this

Abstract A single example of a rearrangement (the elimination of an internal residue) was found in the [M + Na]+ ion of glycosyl polyol under collision-induced dissociation conditions. Previously, this rearrangement of [M + Na]+ was considered as unbelievable.

Abstract The axial aberration of the ion-optical system of a static mass analyzer is one of the main factors limiting the transmission and sensitivity of the instrument. We described an algorithm for selecting the optimal collimating system for a mass analyzer, which makes it possible to decrease this aberration effectively, with minimal loss in the intensity of the mass spectral lines. The algorithm

Abstract A comparative analysis of the results of using the method described in GOST (State Standard) 33490-2015, and an original method for the detection and quantification of markers of diary product adulteration with vegetable oils, 4-desmethylsterols, by gas chromatography/electron ionization mass spectrometry was performed. It was shown that, using the original procedure, one can avoid false positive

Abstract We proposed a method for determining the presence of trace amounts of adducts of isopropylmethylphosphonic acid (IMPA) and cyclohexylmethylphosphonic acid (CMPA), biomarkers of exposure to sarin and cyclosarin in a body, with a tripeptide (Tyr-Thr-Lys). The method is based on plasma trypsinolysis with the formation of stable adducts IMPA–Tyr-Thr-Lys and СMPA–Tyr-Thr-Lys and their detection

Abstract Investigation of original drugs involves a study of pharmacokinetics and metabolism. Most investigations use HPLC/MS analysis. With the use of the active ingredient of a non-benzodiazepine anxiolytic Fabomotizole [2-(2-morpholinoethylthio)-5-ethoxybenzylimidazole dihydrochloride)] and its metabolite as an example, it was found that capillary gas chromatography–mass spectrometry with positive

Abstract Analyses of the composition of exhaled gases are among important areas of non-invasive medicine. Diagnostics based on the analysis of exhaled gases offers several advantages over traditional laboratory methods. An analysis of a gas mixture is safe for the staff, because it does not involve chemical and biological fluids. The analysis is relatively inexpensive, takes little time, and ensures

Abstract Eleutherococcus senticosus is a plant with medicinal properties due to the presence of glycosides, called eleutherosides А, В and В1, C, D, E, and F, in its roots and rhizomes. In this paper, a procedure for the simultaneous determination of Eleutheroside B and Eleutheroside E in dry samples of Eleutherococcus senticosus roots from different manufactures by high performance liquid chromatography/tandem

Abstract A multipurpose reagent, p-methoxyphenacyl bromide, is proposed for the derivatization of polar products of the degradation (markers) of nerve agents, which allows their determination by high-performance liquid chromatography with tandem mass spectrometric detection or by gas chromatography in combination with high-resolution mass spectrometry. The reaction conditions for the derivatization

Abstract The analysis of DNA fragments by capillary gel electrophoresis is in wide current used in the practice of research and testing laboratories primarily for highly accurate and highly sensitive identification of organisms by their DNA traces separated from biological test materials and amplified by polymerase chain reaction. A constantly growing flow of examinations performed using this method

Abstract The review presents exhaustive information for the last 5 years on the trends and methods of research, development, and application of enantioselective voltammetric sensors on the basis of new chiral materials for the recognition of enantiomers of biologically active and medicinal compounds. Enantioselective sensors on the basis of chiral Cu, Au, Ag, Pt, and Pd nanoparticles and single crystals

Abstract The chromatographic analysis of food products for trans isomers of monounsaturated fatty acids, which are harmful components, in the presence of an excess of useful cis isomers is considered as a complex problem of considerable current interest. The separation of substances by gas–liquid chromatography occurs in accordance with two mechanisms with different selectivity for geometric isomers

Abstract In this study, a selective and easy colorimetric probe was developed for the detection of silver ions. This system relied on the aggregation of gold nanoparticles (AuNPs) with ammonium pyrrolidine dithiocarbamate (APDC) and its anti-aggregation in the presence of silver ions. APDC caused the aggregation of AuNPs which resulted in color change from red to blue. However, in the presence of silver

Abstract An enantioselective voltammetric sensor based on a glassy carbon electrode modified with a composite of a polyelectrolyte complex of chitosan, Carboblack C graphitized thermal carbon black, and 3,4,9,10-perylenetetracarboxylic acid is developed for the recognition and determination of tyrosine enantiomers. The enantioselectivity of the sensor is due to the formation of self-organizing chiral

Abstract The series of the interaction products of substituted benzaldehydes XC6H4CHO with several aliphatic diols (ethanediol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, and racemic 2,3-butanediol) were characterized for the first time by analytical parameters required for their chromatography–mass spectrometric identification: electron ionization mass spectra and gas-chromatographic retention

Abstract This paper describes a novel method for the sensitive determination of imidacloprid using homogeneous liquid−liquid microextraction via flotation assistance (HLLME-FA) in water samples. After the extraction procedure, low density organic solvent was separated by air flotation. Various parameters affecting the extraction efficiencies such as the types of extraction and homogeneous solvents

Abstract Since its inception, the method of capillary electrophoresis has developed into a powerful analytical tool for the analysis of food and environmental samples, forensic and bioanalytical analysis. The review considers the main trends in the development of the electrophoretic method: the use of nanomaterials as a fundamentally new approach to the electrophoretic separation of analytes; search

Abstract In this work, two naphthalene scaffolds dangling around a benzene moiety as a colorimetric and fluorimetric probe for Fe3+ in aqueous media have been reported. Recognition processes of Fe3+ were shown to be scarcely influenced by other coexisting metal ions. The probe exhibits a turn on colorimetric and a turn off fluorimetric detection of Fe3+ ions. The association constant for sensor 1–Fe3+ complex

Abstract A simple fluorescent chemosensor 2-(furan-2-yl)-4,5-diphenyl-1H-imidazole (P1) based on an imidazole furan conjugate has been designed, synthesized and characterized. Fluorimetric studies on chemosensor P1 showed excellent selectivity toward Cu2+ ions over other metal ions in aqueous media through a “turn on−off” process. A possible reverse photoinduced electron transfer mechanism is proposed

Abstract A simple, rapid and accurate stability-indicating reversed-phase liquid chromatographic method was developed and validated for the simultaneous determination of aspirin, caffeine and ephedrine in weight loss formulations, human plasma and for the study of in vitro drug−drug interactions. Optimum chromatographic separation for aspirin, caffeine and ephedrine was achieved within 4.5 min on a

Abstract In determining thiocyanates by photometry as complexes with iron in chloride-containing solutions, it is necessary to take into account the complex dependence of the absorbance of solutions on their composition because of the formation of iron chloride complexes, as well as ternary colored iron thiocyanate and chloride complexes. A mathematical model relating the equilibrium concentrations

Abstract The fabrication of the electrode surface has been a target of investigation for several researchers trying to increase the analytical performance of electrochemical sensors. Here, the use of a trihexyltetradecylphosphonium ionic liquid functionalized multiwalled carbon nanotubes and zinc oxide nanoparticles as an active nanocomposite for the electrochemical detection of isoniazid (INZ) has

Abstract A novel method for the determination of pyrethroid pesticide residues in wooden toys was developed. Wooden toy samples were extracted with petroleum ether−acetone (1 : 1, v/v), cleaned up on a florisil solid phase extraction cartridge and determined by gas chromatography equipped with electron capture detector (GC−ECD), followed by validation using gas chromatography−mass spectrometry (GC−MS)

Abstract A liquid chromatography−quadrupole time-of-flight mass spectrometry (LC−QTOF/MS) based plant metabolomics approach was established to investigate the metabolic profiles of the Cinnamomum camphora leaves of four different areas. The LC−QTOF/MS data were subjected to principal component analysis (PCA) and orthogonal partial least squared discrimination analysis (OPLS-DA) to find the potential

Abstract A novel method for the determination of butachlor and fipronil in liquid milk has been developed using ionic liquid dispersive liquid-liquid microextraction coupled with ultra-high performance liquid chromatography (UHPLC). The optimum extraction conditions were determined to be 60 μL of 1-octyl-3-methyl imidazole six fluorine phosphate extraction solvent, 1000 μL of acetonitrile as the dispersing

Abstract Auxins play a very important role in plant development and growth. Herein a rapid and convenient method was developed for the quantification of total auxins including indole-3-acetic acid, indole-3-propionic acid and indole-3-butyric acid in mung bean sprouts by means of spectrofluorometry. Based on the same fluorescence properties of the compounds, a linear working curve was established between

Abstract Published data on various versions of the homogeneous liquid–liquid microextraction (HLLME) of organic compounds are generalized and systematized, and a classification of these versions is given. The main HLLME procedures are discussed. Examples of the application of HLLME to the separation of organic compounds in the analysis of environmental samples, food products, and biological fluids

Abstract We studied the component composition of the essential oil of garden sage (Salvia officinalis L.), obtained by various extraction methods. Essential oils were obtained by hydrodistillation and subcritical CO2 extraction, supercritical fluid extraction, and subcritical extraction with solid-phase and liquid–liquid preconcentration. The components were identified by comparing the recorded mass

Abstract An enhanced swift indirect method for the determination of both free and bound 3-monochloropropane-1,2-diol has been established. The advantages include reduced sample preparation time (1 h instead of several hours), rapid triple quadrupole gas chromatography−mass spectrometry detection (12 min rather than 30 min in average) combined with amplified selectivity and sensitivity. The enhanced

Abstract X-ray photoelectron spectroscopy (XPS) is a really specific and sensitive method for surface analysis. The monitoring of antimony concentrations in polyethylene terephthalate (PET) bottles by XPS analysis is a new method for the characterization of bottled water contamination by antimony which frequently comes into contact with food and drink. The elevation of Sb concentrations in bottled

Abstract Methotrexate (MTX) is the only chemotherapy drug that is routinely monitored by therapeutic drug monitoring service in Malaysia government hospitals. The patients with MTX plasma concentration exceeding 0.4 μM for 48 h are at higher risk to develop toxicities such as nephrotoxicity, hepatotoxicity, neurotoxicity, mucositis and myelosuppression. The aim of this study was to develop and validate

Abstract Pb(II) ions were separated/preconcentrated and detected by a two-step preconcentration method (Amberlite CG-120 resin and slotted quartz tube (SQT) flame atomic absorption). The first preconcentration step was the adsorption of Pb(II) on Amberlite CG-120 resin in the drinking, spring and lake water samples before detection and then its elution using 5 mL of 3 M nitric acid. The second preconcentration

Abstract Azo dyes constitute about 66% of all colorants and they are widely used in industries such as textiles, plastics, ceramics, cosmetics and food. However, due to the reductive cleavage of some azo dyes into carcinogenic aromatic amines, many countries have set concentration limits or have banned the use of these azo dyes. Selected aromatic amines that pose health risk to consumers were simultaneously

Abstract A similarity of electron ionization mass spectra of various alkyl esters of benzene-1,2-dicarboxylic (phthalic) acid places special demands on the reliability of the identification of monoalkyl phthalates, often recognized as dialkyl phthalates and vice versa. An original mass spectrometric criterion is proposed for the group identification of monoalkyl phthalates (assignment to a subgroup

Abstract We conducted a comprehensive multiscale study of a sample of a lunar soil particle with the minimum impact on its structure using a new methodological approach. Qualitative and quantitative information was obtained on the structure and composition of the sample over a scale range from hundreds of micrometers to tens of nanometers. The proposed correlation approach enables high-precision studies

Abstract 2-(N-pipyridino methyl)-1-cyano cyclohexanol was synthesized, characterized and used as an ionophore in construction of polyvinyl chloride (PVC) potentiometric sensor for Hg2+ determination. The best result was obtained with membrane composition of PVC (29%), sodium tetraphenylborate as ionic additive (1%), 2-(N-pipyridino methyl)-1-cyano cyclohexanol (12%) and dibutylphthalate (58%). The

Abstract This paper presents a new technique of hydrocole (bacteria, blue−green algae, phytoplankton, zooplankton, sponges, fish oil and seal fat) fatty acids (FA) methyl esters determination by gas-liquid chromatography. The polyunsaturated fatty acids (PUFA) contents in these objects were different. The distinguishing features of the technique are the next ones: efficiency, lipid extraction recovery

Abstract Dispersive liquid–liquid microextraction (DLLME) is one of the most promising methods of the microextraction preconcentration of organic compounds. This method is eco-friendly, simple, and universal; in comparison with conventional extraction, the consumption of the reagents and solvents, the time of extraction, and the cost of analysis in this method are reduced. For a short time from the

Abstract A naphthoquinone-functionalized hybrid organic-inorganic silica-based fluorescent sensor was designed, synthesized and characterized by X-ray diffraction, N2 adsorption-desorption, thermogravimetric and infrared spectroscopy analysis. Fluorescence properties of the prepared sensor were investigated in the presence of different anions under excitation at 305 nm. The fluorescence emission of

Abstract Conditions of the synthesis of nanoparticles of ractopamine molecularly imprinted polymers (MIP) by the precipitation method are studied. It is shown that the size and dispersity of MIP particles are largely determined by the nature of the functional and cross-monomers and by the synthesis conditions: temperature, mixing rate, duration of synthesis, and ultrasonic treatment of the polymerization

Abstract Complete decomposition is an essential prerequisite for accurate trace element quantification in geological samples. This work presents a general high-pressure closed digestion approach for rock samples from basic to acidic rocks by inductively coupled plasma mass spectrometry. Using HNO3−HF mixed system, different geological reference materials have been investigated for trace element determination

Abstract The present study suggested three different highly sensitive luminescent systems based on the employment of silver nanoparticles (NPs), copper oxide nanoparticles and gold nanoparticles in the presence of micellar medium sodium dodecyl sulfate (SDS) for the detection of ascorbic acid in some fruit juices. The fluorescence spectral behavior of ascorbic acid was detected at λem of 420 nm after

Abstract The contribution of Russian experts to the development of HPLC is significant; they have proposed and developed new chromatography methods, adsorbents, and instruments. New applications of HPLC are proposed, in particular, for the separation of viruses, nanoparticles, optical isomers, peptides, and other compounds. HPLC has become widely used in Russia for the control of contamination of food

Abstract Regularities of the electrooxidation of sulfite ions in an alkaline medium (рН ≥ 8; LiClO4, KNO3, Na2SO4, NaOH) on a composite carbon-containing electrode modified by submicron (300 nm or smaller) gold particles are studied using cyclic voltammetry. The electrocatalytic nature of the analytical signal is substantiated; a scheme of the oxidation process is proposed. A procedure for the preliminary

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