Химия

The unmodified and modified by polyaniline and nanoparticles planar potentiometric sensors on the basis of tetradecylammonium associates with a complex silver (I) – cefazolin are created. Optimum ratios of components in carbon-containing ink are established: 30–32% carbon powder, 16–18% polyvinylchloride, 48–50% dibutylphthalate and 1–3% of electrode active compound (EAC). Planar sensors of two types are examined: electrode active compounds, electrode active compound and modifiers were added into in carbon-сontaining ink.

The article presents information about the possibility of using sodium arsenite hydrolyzed as a new type of arsenic-containing raw material for obtaining marketable products of various qualities. The methods of purification of arsenic (III) oxide as the main product of sodium arsenite hydrolyzed processing to various degrees of purity (3-6N) are given, which allows using it as a raw material for the synthesis of a wide range of arsenic compounds: arsenic acid, elemental arsenic, arsenic trichloride.

Iminodisuccinates of several rare earth metals (REM) have been synthesized as a result of reaction between freshly prepared ammonia iminodisuccinate and REM chloride soltuions at pH 3. According to element analysis data, the chemical composition of synthesized salts is MeHC8H7O8N · nH2O, where Ме = La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, n = 1–5. Synthesized compounds were further analyzed via X-ray diffraction and thermogravimetric analysis. According to X-ray data, REM iminodissucinates form well-defined crystals in two distinct isostructural groups.

Hydrodynamic, optical, colloid-flocculating, film-forming and structural morphological properties of diluted chitosan solutions (50–640 kDa) in acetate buffer (0.33 М СН3СООН + 0.2 М СН3СOONa), both initial ones and stored for ~1,850 days, were studied. It has been established that the decrease in the intrinsic viscosity of solutions over time is manifested for the reprecipitated and high-molecular-weight samples of chitosan to a greater degree.

Higher fungi – basidiomycetes play significant role as food and biological subjects for establishing the regularities of the living systems’ operation, development and response to the different-nature effectors impact. Insufficient activity of the living organisms’ antioxidant system interfering the ability of overcoming the negative consequences of oxidative stress (excessive level of free radicals in cells) is believed to be a reason for the organisms aging and death.

Colorimetrically using the MTT assay the cytotoxic activity of 5-aryl-1,2,3,4,5,6-hexahydrobenz[4,5]imidazolo[1,2-a]quinazolines and a tautomeric mixture of 4-amino-2-phenyl-6H-pyrido[1,2-a] pyrimidin-3-carbonitrile with 2-(phenyl(pyridin-2-ylamino)methyl)- malononitrile was screened.

With three-component condensation of 1,2,4-triazol-3-amine, hydroxy-substituted aromatic aldehyde (2-hydroxybenzaldehyde, 4-hydroxybenzaldehyde, 4-hydroxy-3-methoxybenzaldehyde, 2-naphthalene-carbaldehyde), cyclohexanone, the aldehyde component has a defining impact on the shaping of triazologic hydroquinazolines with different types of rings articulation and the position of the double bond in them (C4a–C5 and C4a–C8a).

The reaction of maleic anhydride with 1,2-phenylenediamine when heated in an aprotic solvent, regardless of temperature, proceeds with the initial formation of the primary addition product, namely, 4-[(2-aminophenyl)amino)-4-oxobut-2-enoic acid, which further undergoes heterocyclization within two ways, due to the presence of several electrophilic centers in the molecule, depending on the reaction conditions.

Transport properties of the plasticized polyvinylchloride membranes on the basis of tetradecylammonium associates with complex connections silver (I) – cefotaxime in the conditions of a diffusive mass transfer and a direct current are investigated. With variation of concentration of electrode active substances (0.5; 1; 2; 3%), the external solutions contacting with membranes (10-2–10-7 M). It is established that resistance of membranes depends on the content of electrode active substances (EAS) and concentration of perimembrane solutions of a cefotaxime.

Amoxicillin is a semi-synthetic aminopenicillin ?-lactam series with a wide spectrum of antibacterial activity against many gram-positive and gram-negative microorganisms. It is included in the list of essential drugs. Test systems for the detection and identification of amoxicillin are missing. We have obtained indicator papers with immobilized ninhydrin and p-dimethylaminobenzaldehyde for the test determination of amoxicillin. The reaction conditions were selected, depending on the temperature and time.