Reaction of a Fischer base and its derivatives with benzoylacetaldehydes

The corresponding 2-(3-benzoyl-2-propen-1-ylidene)indolines, which exist in the form of merocyanines and do not display tendencies to undergo intramolecular cyclization to the spiro form, were obtained as a result of the reaction of 1,3,3-trimethyl-2-methyleneindoline and its analogs with p-substituted benzoylacetaldehydes.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 202–206, February, 1981.     

Interaction of shungite carbon nanoparticles with blood protein and cell components

We have analyzed and compared the effects of aqueous dispersion of shungite carbon nanoparticles, fullerene C₆₀, and nanodiamonds on structure, dynamics, and thermodynamic and redox properties of blood proteins (serum albumin and hemoglobin), proteins of erythrocyte ghost membranes as well as on erythrocyte integrity and aggregation.. All the nanomaterials dispersions have induced similar effects; however, nanodiamonds have not influences the redox properties. Basing on the results, the experimental and theoretical approaches presented can be employed to estimate the effects of biological structures contact with the nanoparticles on the bioreactivity.     

Over-pressure TLC variant on a plate with an enclosed sorbent layer

An over-pressure TLC variant with an enclosed sorbent layer and forced flow of the mobile phase was suggested. A simple new type device for its realization was developed.Translated from Izvestiya Akademioi Nauk. Seriya Khimicheskaya, No. 3, pp.771–773, March, 1996.     

Chromatofocusing of peptides on a sulfo-cation-exchange sorbent

Simple mobile phases containing no more than two active components were proposed for the formation of ascending pH gradients in a column filled with a sulfo-cation-exchange sorbent. The smoothest nearly linear pH gradients were obtained with the use of citric acid and Tris or NaH₂PO₄ and Tris as active components of the eluent and adjusting ionic strength (up to 0.1–0.3) in the starting solution or eluent; however, in the case of UV detection, the use of NaH₂PO₄ is preferable because of lower light absorption. Potentialities of the proposed approach in the chromatography of peptide mixtures on a sulfo-cation-exchange sorbent were demonstrated. Additions of acetonitrile to mobile phases improve the selectivity of the separation of peptides.     

槲皮素分子印迹聚合物的制备及固相萃取性能研究

采用分子印迹技术, 以槲皮素为模板分子, 丙烯酰胺为功能单体, 乙二醇二甲基丙烯酸脂为交联剂, 通过热引发聚合, 制备了槲皮素分子印迹聚合物, 并通过装入固相萃取柱试验了聚合物对槲皮素的选择性能. 结果表明, 该分子印迹聚合物对槲皮素具有高度选择性, 为从天然产物中高效分离富集黄酮活性成分槲皮素提供了一种新材料.     

Porous biosorbents on the basis of methacrylic acid and triallylisocyanurate

Novel granular biosorbents of cellular structure were obtained by suspension copolymerization of methacrylic acid and a trivinylic cross-linking agent, triallylisocyanurate. The main advantage of these sorbents in comparison with the conventional ones is the absence of a dense shell on the surface. The cellular structure is characterized by the negative radius of curvature of the polymer phase surface. Investigations into acidic properties of carboxyl groups in the series of copolymers with various concentration of the cross-linking agent (from 1 to 20 mol.%) revealed no cooperativity of ionization of carboxyl groups typical of conformationally stable cross-linked polyelectrolytes. The regularities of reversible binding of model proteins to the copolymers of methacrylic acid with triallylisocyanurate were studied; the possibility of chromatographic separation of proteins using sorption and reversible desorption on the obtained cation-exchange resins was demonstrated.     

Magnetite nanoparticles surface-modified with a zinc(II)-carboxylate Schiff base ligand as a sorbent for solid-phase extraction of organochlorine pesticides from seawater

Magnetite nanoparticles were surface-modified with mercaptoacetic acid (MAA), complexed with Zn(II), and then treated with the dual Schiff base (referred to as imine-based ligand; IBL; obtained by reaction of p-aminobenzoic acid and 2,3-butanedione) to give particles with an architecture of type Fe₃O₄@MAA@IBL. These are shown to be viable sorbents for magnetic solid phase extraction of organochlorine pesticides (OCPs) from seawater samples. Efficient extraction of the OCPs probably is due to lone pair-π, π-complexation and π-interactions. The sorbent was characterized by transmission electron microscopy, scanning electron microscopy, FT-IR and energy-dispersive X-ray spectroscopy. The effects of the volumes of sample, sorbent dosage and eluent, adsorption and desorption times, and the salinity of the sample on the extraction efficiencies were optimized. The OCPs (heptachlor, aldrin, dieldrin, p,p’-DDE and p,p’-DDT) were quantified by gas chromatography with microelectron capture detection. Under optimal conditions, the limit of detections range was between 1.0 and 1.9 ng L^?1. The enrichment factors are between 84.1 and 99.9 %. The sorbent was applied to the rapid extraction of trace quantities of OCPs from seawater samples and gave good relative recoveries (78 to 108 %) and relative standard deviations (<8.3 %).

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Graphical Abstract Fe₃O₄ nanoparticles were functionalized with mercaptoacetic acid. The carboxylate was coordinated with Zn(II) and the ligands were immobilized via coordination with Zn(II). The lone pair-π, π-complexation and π-interaction of modified magnetite nanoparticles made this sorbent effective for extraction of organochlorine pesticides.

     

The method of concentrating a substance from a solution in a stationary sorbent layer and its theoretical basis

The principle of concentrating a substance from a mixture flow in a stationary sorbent layer of infinite length that was previously developed for gas chromatography is extended to liquid chromatography. Translated fromIzevestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1063–1065, May, 1997.     

Chromatographic behavior of a model mixture of phenols on a sorbent modified with zinc phthalocyanine

The chromatographic retention of a number of phenols on Diasphere-110-C18 sorbent modified with a zinc octa-4,5-carboxyphthalocyanine was studied. It was examined whether the Scott-Kucera and Snyder-Soczewinski displacement models of retention could describe the experimental data obtained. Both the models proved to be adequate in describing the experimental data at contents of the polar component in the mobile phase of 8–70%. The phenols were found to be eluted in order of increasing hydrophobicity.     

Solid-phase extraction with a dibutylmelamine-imprinted polymer as triazine herbicide-selective sorbent

Triazine herbicide-selective polymer spheres were prepared by molecular imprinting using dibutylmelamine (DBM) as a template in suspension polymerization, and were utilized in solid-phase extraction (SPE) of atrazine. Atrazine-selective SPE was successfully demonstrated with a recovery of ca. 97% and an enrichment factor of 50, proving the good aptitude of DBM as the template species for developing a specific sorbent for triazine herbicides. It is also noteworthy that DBM-imprinted polymers have no possibility of disturbance in agrochemical analyses even if DBM remained in the polymer, which may occur by insufficient washing at the stage of removing the template to yield the binding sites, increasing the availability of imprinted polymers for practical applications.     

Porous-layer capillary gas chromatography columns with a hybrid structured sorbent based on alkyltriethoxysilane

Porous-layer capillary columns with a hybrid organic-inorganic sorbent based on structured silica are described. Properties of the prepared columns are discussed. Examples of separating C₁–C₄ hydrocarbons and a mixture of solvents on the obtained columns are presented. It is shown that changes in the organic component content of the original sol make it possible to control the selectivity of porous-layer columns.     

A multicapillary gas chromatographic column with a Sol-Gel sorbent based on aluminum oxide

A multicapillary gas chromatographic column with an adsorption layer based on alumina was prepared. The column allowed the high-speed separation of C₁-C₄ light hydrocarbons to be performed in 8–12 s. The possibility of creating columns with various selectivities was demonstrated.     

Solid-phase extraction of polar compounds with a hydrophilic copolymeric sorbent

A new synthesized copolymer based on N-vinylimidazole-divinylbenzene (VIm-DVB) was tested as a sorbent for the solid-phase extraction (SPE) of polar analytes. In the on-line SPE, this synthesized sorbent enabled 100 ml of sample to be preconcentrated with recoveries as high as 80% for oxamyl, phenol (Ph) and derivates, bentazone and (4-chloro-2-methylphenoxy)acetic acid (MCPA). For the off-line SPE, 1000 ml of sample was extracted and recoveries were higher than 92% for all compounds with the exception of oxamyl (83%) and methomyl (78%). The VIm-DVB sorbent gives better recoveries than the previously synthesized 4-vinylpyridine-divinylbenzene (VP-DVB) resin and similar to such highly crosslinked commercial sorbents as LiChrolut EN or Oasis HLB. Real water samples were used to validate the on-line SPE method. Linearity was good and detection limits were between 0.1 and 0.2 microg l(-1).     

Analytical characterization of a silica gel sorbent with thioetheric sites

The sorption behavior of a newly synthesized silica gel sorbent with thioetheric sites (STS) towards microgram levels of Au(III), Pt(IV) and Pd(II) was studied. Au(III) is quantitatively (>95%) sorbed in the pH region of 1–9. The sorption of Pt(IV) starts at pH 1 and does not exceed 25% in the entire pH region examined. The sorption of Pd(II) starts at pH 7 and reaches 80% at pH 9. The sorption of Au(III) on STS at pH 1 is not affected by milligram amounts of Ni(II), Zn(II), Fe(III), Cu(II), Pb(II), Cd(II) or Co(II). Au(III) is quantitatively eluted with a 5% aqueous solution of thiourea. The adsorption capacity of STS towards Au(III) is 195 mg g⁻¹. The detection limit (DL) of Au(III) (3σ, n = 9) is 25 ng mL⁻¹. The RSD at a level of 10 × DL is about 2%. Solid-phase extraction of trace amounts of Au(III) on the STS sorbent, followed by its flame AAS determination in the eluate was applied to the determination of gold in geological samples. The results obtained for the gold content in the samples were in good agreement with those of the ICP-AES analysis.     

A study of sorption processes on a polyamide sorbent

Conclusions Using quercetin and dihydroquercetin as examples, it has been shown that the adsorption of flavonoids increases with a decrease in the polarity of the solvent and depends on the molecular weight of the polyamide sorbent. The presence of a double bond in quercetin leads to a higher sorption activity than the dihydroquercetin.Khimiya Prirodnykh Soedinenii, Vol. 4, No. 6, pp. 349–352, 1968     

The study of the structural, sorption, and electrochemical properties of a natural composite shungite

An integrated study of the structural, sorption, and electrochemical properties of a natural mineral shungite has been carried out. The composite nature of the mineral has been shown to predetermine its basic physicochemical characteristics. The isosteric heat of water adsorption $ \bar Q_a An integrated study of the structural, sorption, and electrochemical properties of a natural mineral shungite has been carried out. The composite nature of the mineral has been shown to predetermine its basic physicochemical characteristics. The isosteric heat of water adsorption = 70 kJ/mol, as estimated by calorimetry and gas chromatography, reflects the interaction of its molecules with vicinal hydroxyl groups of the silica component of shungite. Adsorption heats, = 40–45 kJ/mol, is governed by the carbon moiety of the sorbent. Higher adsorption heats of benzene on shungite, as compared with those of hexane, are indicative of the interaction of its molecules with active sites of the carbon and silica moieties of the mineral. The type and number of these sites have been determined by potentiometry and conductometry. The obtained adsorption parameters of shungite with respect to anionic organic compounds enable us to recommend its application as a sorbing material for filtration. Original Russian Text ? Yu.I. Tarasevich, S.V. Bondarenko, V.E. Polyakov, A.I. Zhukova, Z.G. Ivanova, V.V. Luk’yanova, G.N. Malysh, 2008, published in Kolloidnyi Zhurnal, 2008, Vol. 70, No. 3, pp. 384–391.