Chemistry

Potentiometric Sensors for Determination of Cefepime in Water and Biological Environments

Authors: Kulapina O. I., Kulapina E. G., Karenko V. A.

Potentiometric cefepime sensors based on an organic ion-exchanger such as cefepime with tetraphenylborate are developed. The optimum membrane composition is established. The surface and volume properties of membranes are investigated. The constant of dissociation of the ion-exchanger in a membrane phase is calculated by stationary resistance. Potentiometric determination of cefepime in water and biological environments is present.

Phase Equilibria in the Twocomponent System n-nonadecan – Cyclododecane

Authors: Petrov E. P., Garkushin I. K., Kolyado A. V.

Method of low-temperature differential thermal analysis using a differential scanning calorimeter of heat flow was first studied system n-nonadecane – cyclododecane. The studied systems are of the eutectic type. Alloy of eutectic composition contains 37,0 wt % of cyclododecane and melts at a temperature of 20.4 °C.

Research of a State of Some the Cephalosporin Antibiotics in Water Environments by Spectrophotometry

Authors: Kulapina O. I., Karenko V. A., Kulapina E. G.

An express authenticity estimation of some cephalosporin antibiotics of II and III generations are developed by spectrophotometry. An identity of drugs such as cefotaxime (Russia) and claforan (France), cefuroxime (Russia) and cefuroxime axetil (England) is shown.

Definition of Arginine in the Mixed Solutions Monoaminooksidasy α-aminoacids

Authors: Varygina O. V., Chernova R. K., Petrovich M. V.

The state of monoaminooksidasy arginine and α-amino acids in aqueous media. Built chart the distribution of ionized forms of arginine and valine at varying pH. Pakistan the possibility of Express electoral pH titrations of arginine in mixed solutions monoaminooksidasy α-amino acids. The interval defined concentrations of 46,3–217,8 mg . Error does not exceed 5.5%.

Detection of Pharmaceuticals Using Magnetic Sers-active Core–Shell Structures

Authors: Markina N. E., Pozharov M. V., Zakharevich A. M., Burmistrova N. A., Markin A. V.

The work is devoted synthesis, investigation and application of composites based on calcium carbonate microspheres, with embedded nanoparticles of magnetite (Fe3O4), coated by silver nanostructured shell. This composite (SERS-substrate) was used for surface-enhanced Raman spectra (SERS) registration of rhodamine 6G and different pharmaceuticals such as ipratropium bromide, chloramphenicol, propranolol, pindolol, tamoxifen, diltiazem.

Sorption-fluorimetric Determination of Enrofloxacin with Magnetite Nanoparticles Modified by Polyethylenimine

Authors: Egunova O. R., Reshetnikova I. S., German S. V., Kazimirova K. O., Khabibullin V. R., Zhelobitskaya E. A., Shtykov S. N.

A technology for magnetite nanoparticles surface modification by polyethylenimine was proposed. The sizes of the nanoparticles using transmittance microscopy method were determined. The influence of pH, time of mixing, sorbent and antibiotic concentration on the enrofloxacin sorption was investigated and optimal conditions of extraction were found. Enrofloxacin sorption from plasma-modelling solution was studied and was shown that that in optimal conditions the extent of sorption is 78% and desorption from magnetite modified nanoparticles using ethanol-sodium dodecylsulfate is 95%.

Synthesis of Spiro-fused Hydropyrimidinthiones with Use of Thiobarbituric Acid

Authors: Klochkova I. N., Aniskov A. A., Schekina M. P., Tumskiy R. S.

The conditions for the preparative synthesis of spiro-fused hydropyrimidinthiones based on carbonyl substrates and thiobarbituric acid were found. Schemes of condensation carbo- and heterocyclization are presented. Regio- and stereoselectiveness processes was established.

Stereochemical Aspects of Reaction of 1,3-dipolar Cycloaddition in a Row of Conjugated Enones

Authors: Aniskov A. A., Klochkova I. N., Schekina M. P., Andreev K. A., Tumskiy R. S.

The reaction of 1,3-dipolar cycloaddition of conjugated aryl(hetaryl) methylideneacetones, which containing various peripheral substituents, with azomethine ylides was carried out. It was established that the interaction is not chemoselective and proceeds with the participation of two non-equivalent reaction centers of dipolarophile with high diastereoselectivity. The products of cycloaddition were a mixture of structural isomers endo-cycloaddition. Monoenone transform to spyropyrrolidines with high endo-stereoselectivity.

Determination of Caffeine and Some Food Additives Wines, Energy and Soft Drinks

Authors: Selifonova E. I., Salkova D. V., Chernova R. K.

The method of capillary electrophoresis to determine the content of caffeine and food additives: ascorbic (E300), sorbic (E200), benzoic (E210) acids; sweeteners – saccharin sodium (E954), acesulfame potassium (E 950) in wines, energy drinks and tea. The comparative characteristic of the caffeine content, and the aforementioned food additives in beverages. A comparison with the corresponding regulations. It is shown that the concentration of benzoic acid in beverages above the maximum allowable concentration in beverages Flesh and MONETO.

Determination of the Main Substances in the Preparations of Cephalexin and Cefuroxime Axetil

Authors: Kulapina E. G., Karenko V. A., Kulapina O. I.

Techniques of determination of the main substances in capsules of cephalexin and tablets of cefuroxime axetil have been elaborated. For separation of ancillary compounds, the two modes have been approbated, i.e. filtration and centrifugation. The advantage of the second means has been shown.

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