Vol 73, No 3 (2018)

The effect of the chemical nature of the surface of detonation nanodiamond on the adsorption of an antibiotic is revealed with the help of tritium-labeled amikacin. It is found that nanodiamonds with a carboxylated surface (S_sp = 283 ± 5 m²/g) chemisorbed twice as much amikacin as nanodiamonds with a hydrogenated surface (S_sp = 289 ± 5 m²/g): 48 and 22 mg/g, respectively. Maintaining nanodiamonds with immobilized amikacin in the form of hydrosol for 1 month results in a release of up to 9.6 and 6.4 mg/g of the antibiotic, respectively. The results demonstrate the possibility of creating an amikacin delivery system based on nanodiamonds.

Thermodynamic simulation of phase equilibria is carried out, allowing us to calculate the liquidus lines for the phase diagrams of the Cu₂O–Na₂O, Cu₂O–K₂O, and K₂O–Na₂O oxide binary systems, and also the liquidus surface of the Cu₂O–Na₂O–K₂O ternary system. In the course of the work, the values of the model parameters used to calculate the activity of the oxide melts of the investigated systems are determined. The values of the activity of copper oxide and sodium oxide in the Cu₂O–Na₂O system for a temperature of 1250°C are calculated. The activity data are characterized by negative deviations from Raoult’s law. During the simulation, the enthalpy and entropy of the formation of a KNaO compound from the liquid components are estimated. According to the calculations, the liquidus surface of the phase diagram of the Cu₂O–Na₂O–K₂O ternary system has two points of invariant equilibria.

Using the mathematical planning of the experiment by the method of Latin squares, we optimize the adsorption conditions for Bi(III) from dilute aqueous solutions and its desorption from the surface of silica gel L100/250. It is found that the maximum degree of adsorption (95–98%) is reached at pH 4.5, near the zero-charge point of silica gel and under the domination of the Bi(OH)3 monomeric hydroxyl species in solution. The adsorption time does not exceed 30 min with an adsorbent weight of 0.4 g, and the maximum desorption is observed when Bi(III) is eluted with a 0.5 M nitric acid solution for 20 min. An adsorption-spectroscopic procedure for the determination of Bi(III) with Xylenol Orange is developed. The calibration dependence is linear in the concentration range of 0.25 to 6.0 μg/mL, and the detection and determination limits are, respectively, 0.09 and 0.28 μg/mL. The procedure is tested using standard reference samples of tungsten ores and molybdenum concentrate; the relative standard deviation does not exceed 4%.

The paper presents an investigation of the antibacterial activity of composites that are obtained based on a natural sorbent with immobilized antibiotics, tetracycline, and doxycycline. Both the investigated composites effectively inhibited Staphylococcus aureus, but were not effective against Escherichia coli. The paper also presents the results of an investigation of the elemental composition and some characteristics of the porous surface of the glauconite sorbent of the Beloozero field in Saratov oblast.

The specific antibodies for viral arthritis-encephalitis and toxoplasmosis in goats is comparatively determined by the ELISA and latex agglutination reaction using strip-dried samples of serum and whole blood on a porous membrane carrier. It is shown that the use of strip-dried samples makes it possible to qualitatively and quantitatively determine specific antibodies and its results are completely consistent with those of the analysis of the liquid samples (serum). This sample preparation method can be used for the safe shipment of blood samples and following serological studies in epizootic monitoring.