S.Yu. Bratskaya

article

Dendrimeric rhodamine based fluorescent probe for selective detection of Au

M.V. Tutov, A.A. Sergeev, P.A. Zadorozhny, S.Yu. Bratskaya, more

Sensors and Actuators B: Chemical > 2018 > 273 > C > 916-920

Dendrimeric rhodamine-derived chemosensor for highly selective determination of Au in aqueous acidic solutions has been developed. The response mechanism is based on the destruction of the dendrimeric molecule to provide fluorescence enhancement via reducing intramolecular quenching. The probe exhibits linear signal response and allows determination of Au content in aqueous solutions from 5 × 10⁻⁸...

article

On/off rhodamine based fluorescent probe for detection of Au and Pd in aqueous solutions

A.Yu. Mironenko, M.V. Tutov, A.A. Sergeev, Voznesenskiy, more

Sensors and Actuators B: Chemical > 2017 > 246 > C > 389-394

A water-soluble turn on/off rhodamine 6G based fluorescent probe for selective detection of Au and Pd ions in aqueous acidic solutions has been developed. The newly designed probe reacts with [AuCl₄]⁻ and [PdCl₄]²⁻ to generate a product with different optical properties. The probe undergoes a remarkable change in its absorption and emission spectrum upon addition of Au and Pd complexes that is associated...

article

H2S optical waveguide gas sensors based on chitosan/Au and chitosan/Ag nanocomposites

A.Yu. Mironenko, A.A. Sergeev, A.E. Nazirov, E.B. Modin, more

Sensors & Actuators: B. Chemical > 2016 > 225 > Complete > 348-353

In this work we present simple technique to fabricate chitosan based nanocomposite coatings containing Ag and Au nanoparticles and investigate the possibility of using these materials as sensitive layer of optical planar waveguide based nonreversible hydrogen sulfide sensors (chemidosimeters). It is shown that chitosan/Ag and chitosan/Au based sensors allows detection of hydrogen sulfide gas at concentration...

article

Effect of polymer backbone chemical structure on metal ions binding by imidazolylmethyl derivatives

A.V. Pestov, Yu.O. Privar, A.Yu. Ustinov, A.V. Voit, more

Chemical Engineering Journal > 2016 > 283 > C > 323-329

Sorption properties of poly(N-(5-methyl-4-imidazolyl)methylallylamine (PAA) and poly(N-(5-methyl-4-imidazolyl)methylethylenimine) (IMPEI) have been investigated and compared with those of imidazolylmethyl derivative of natural aminopolymer chitosan (IMC). We have shown that the structure of polymer backbone has a pronounced effect on sorption of both transition metal cations and noble metals by imidazolylmethyl...

article

Binding Ni(II) ions to chitosan and its N-heterocyclic derivatives: Density functional theory investigation

A.S. Portnyagin, S.Yu. Bratskaya, A.V. Pestov, A.V. Voit

Computational and Theoretical Chemistry > 2015 > 1069 > C > 4-10

Here we report the results of density functional theory (DFT) investigations of Ni²⁺ complexes with chitosan and its N-heterocyclic derivatives – N-(2-pyridylethyl) chitosan (2-PEC), N-(4-pyridylethyl)chitosan (4-PEC), and N-(5-methyl-4-imidazolyl)methyl chitosan (IMC). 11 model structures corresponding to ‘bridge’ and ‘pendant’ types of complexes have been calculated. We have shown that in most cases...

article

Integrated-optical sensors based on chitosan waveguide films for relative humidity measurements

S.S. Voznesenskiy, A.A. Sergeev, A.Yu. Mironenko, S.Yu. Bratskaya, more

Sensors & Actuators: B. Chemical > 2013 > 188 > Complete > 482-487

Here we report on fabrication and properties of integrated-optical sensors for relative humidity detection based on waveguide films of chitosan in neutral and salt forms. Obtained sensors have high sensitivity and short response time over a wide range of relative humidity.

article

Synthesis and properties of isomeric pyridyl-containing chitosan derivatives

S.Yu. Bratskaya, Yu.A. Azarova, A.S. Portnyagin, A.V. Mechaev, more

International Journal of Biological Macromolecules > 2013 > 62 > Complete > 426-432

Here we report on the method of synthesis in gel of a new heterocyclic aminopolymer-N-2-(4-pyridyl)ethylchitosan (4-PEC) via direct addition of 4-vinylpyridine to chitosan that yields a derivative with the substitution degree (DS) up to 0.8. The comparison of reactivity, thermal, spectroscopic, and sorption properties of a new derivative and its isomer N-2-(2-pyridyl)ethylchitosan (2-PEC) is presented...

article

N-(2-(2-pyridyl)ethyl)chitosan: Synthesis, characterization and sorption properties

S.Yu. Bratskaya, Yu.A. Azarova, E.G. Matochkina, M.I. Kodess, more

Carbohydrate Polymers > 2012 > 87 > 1 > 869-875

The method of producing N-2-(2-pyridyl)ethylchitosan (PE-chitosan) with substitution degrees (DS) up to 1.2 has been developed using the “synthesis in gel” approach for direct addition reaction between 2-vynilpyridine and chitosan. Investigation of sorption properties has revealed significantly higher affinity of pyridylethyl fragments to Pt(IV)) and Pd(II) ions compared to the unsubstituted amino...

article

Heavy metals removal by flocculation/precipitation using N-(2-carboxyethyl)chitosans

S.Yu. Bratskaya, A.V. Pestov, Yu.G. Yatluk, V.A. Avramenko

Colloids and Surfaces A: Physicochemical and Engineering Aspects > 2009 > 339 > 1-3 > 140-144

Here we report on solution properties and flocculation performance of polyampholyte chitosan derivatives – N-carboxyethylated chitosans (CEC) – synthesized “in gel” by treatment of chitosan with acrylic acid. We show that carboxyethylation with the substitution degrees (DS) from 0.7 to 1.6 yields water-soluble derivatives, whose isoelectric points (IEP) range from 6.30 to 3.55. At pH>7.5 interaction...

article

Comparative study of electrokinetic potentials and binding affinity of lipopolysaccharides–chitosan complexes

V.N. Davydova, S.Yu. Bratskaya, V.I. Gorbach, T.F. Solov'eva, more

Biophysical Chemistry > 2008 > 136 > 1 > 1-6

Electrokinetic properties of complexes of chitosan (Ch) with lipopolysaccharides (LPSs) from Escherichia coli O55:B5, Yersinia pseudotuberculosis 1B 598, and Proteus vulgaris O25 (48/57) and their size distribution were investigated using ζ-potential distribution assay and quasi-elastic light scattering. The interaction of LPS from different microorganisms with chitosan at the same w/w ratio of components...

article

Interaction of Carboxylic Acids with Chitosan: Effect of pK and Hydrocarbon Chain Length

M.V. Shamov, S.Yu. Bratskaya, V.A. Avramenko

Journal of Colloid And Interface Science > 2002 > 249 > 2 > 316-321

Sorption of acetic, propionic, butyric, valeric, and isovaleric acid on chitosan and cross-linked chitosan was studied in aqueous solutions and water/ethanol mixtures. Langmuir, Freundlich, and Redlich–Peterson equations were used to fit experimental isotherms of sorption. Correlation between maximum sorption and the pK value of every carboxylic acid was found for sorption on chitosan in aqueous solutions,...

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Search results for: S.Yu. Bratskaya

Dendrimeric rhodamine based fluorescent probe for selective detection of Au

On/off rhodamine based fluorescent probe for detection of Au and Pd in aqueous solutions

H2S optical waveguide gas sensors based on chitosan/Au and chitosan/Ag nanocomposites

Effect of polymer backbone chemical structure on metal ions binding by imidazolylmethyl derivatives

Binding Ni(II) ions to chitosan and its N-heterocyclic derivatives: Density functional theory investigation

Integrated-optical sensors based on chitosan waveguide films for relative humidity measurements

Synthesis and properties of isomeric pyridyl-containing chitosan derivatives

N-(2-(2-pyridyl)ethyl)chitosan: Synthesis, characterization and sorption properties

Heavy metals removal by flocculation/precipitation using N-(2-carboxyethyl)chitosans

Comparative study of electrokinetic potentials and binding affinity of lipopolysaccharides–chitosan complexes

Interaction of Carboxylic Acids with Chitosan: Effect of pK and Hydrocarbon Chain Length

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