The work deals with the development of an approach to the determination of chlortetracycline, which combines the preconcentration of the analyte with its subsequent determination by capillary zone electrophoresis. The conditions that ensure the lowest value of the limit of determination for chlortetracycline in aqueous solutions using a Kapel-105M capillary electrophoresis system (Lumex, Russia) are determined, i.e., temperature, time and pressure of sample injection, background electrolyte composition, and detection wavelength. It is shown that the stability of a chlortetracycline solution is maximum at a storage temperature of 0.5°С in the absence of buffer systems or in using a dilute ammonium acetate buffer solution. It is found that the recovery of chlortetracycline by strongly acidic cation exchangers KU-1, KU-2 is higher compared to that by KB-4 and KB-4P2, bearing weakly acidic functional groups. The conditions under which the recovery of the analyte by KU-1 from a phosphate buffer solution is about 90% are determined.

Abstract—The effect of isovalent doping Sc3+ → In3+ on the transport properties is studied for complex oxide BaLaInO4 characterized by the Ruddlesden–Popper structure. It is shown that the introduction of scandium increases the oxygen-ionic and protonic conductivity. In the humid air atmosphere at 500°С, both BaLaInO4 and BaLaIn0.9Sc0.1O4 are the protonic conductors with ~90–95% contribution of proton transfer.

We studied the main electrode functions of carbon paste electrodes (CPEs) modified with 0–20% of dithiooxamidated polysiloxane with respect to palladium(II). The conditions for the potentiometric titration of palladium(II) using modified CPEs as indicator electrodes were selected, namely, pH 1–2, solutions of EDTA and potassium iodide as the titrants; and modifier concentration is 0, 5, and 10%. A procedure was developed for determining palladium(II) in aqueous solutions. The procedure was tested using a GSO solution of palladium(II) and an industrially produced activator Pd-600.

A mathematical model is proposed to describe the behavior of complex compounds of metals during their separation via capillary zone electrophoresis. The model helps explain the possibility of the qualitative and quantitative determination of metal ions in their complexes with organic ligands, predict the order of migration of complexes, estimate their migration times, and choose the best conditions for their determination. It is shown that for labile complexes, the possibility of observing their peak is determined by the conditional stability constant. The corresponding polarity and high electroosmotic flow rate are best suited for the determination of charged complexes of low stability, while the voltage and sample injection should be chosen experimentally with allowance for the selectivity of separation and sensitivity of determination. The calculated migration times and the shape of the calibration curves for complexes of different metals with organic chelating agents agree with the experimental results.

In this paper we present the results of the spectral studies of erosive discharge with tin alloy electrodes and of the generated JFs, and experimentally determine internal energy of JFs using the calorimetric technique.

In this paper melting and crystallization of the indium-gallium alloy with indium content of 4 at. % embedded into the porous glass with pore size of 7 nm were studied using acoustic methods. Temperature dependencies of the velocity and attenuation of the ultrasound were measured in a wide temperature range. The expansion of the temperature range of the melting of -Ga was observed. An anomaly on the temperature dependences of the ultrasound velocity and attenuation near ~223 K was revealed which is probably related with the formation of a small fraction of -Ga.

The phenomenological Landau theory was applied for treating the phase transitions in a thin multiferroic film. The multiferroic phase in the relevant bulk was assumed to emerge following two successive phase transitions of the second order. The coupling between the order parameters was implied to be biquadratic as for a multiferroic-magnetoelectric. The variation of the free energy density functional yielded a system of two nonlinear differential Euler-Lagrange equations with four boundary conditions. The boundary value problem was analyzed numerically. It was shown that the phase diagram in the film can differ radically from that in bulk for particular sets of the phenomenological parameters.

The paper presents the results of studying the crystallization and melting processes of Ga–In eutectic alloys, which are embedded in opal matrices, using acoustic and NMR methods. The indium concentrations in the alloys were 4, 6, 9, and 15 at %. Measurements were performed upon cooling from room temperature to complete crystallization of the alloys and subsequent heating. It is revealed how the size effects and alloy composition influence the formation of phases with α- and β-Ga structures and on changes in the melting-temperature ranges. A difference was observed between the results obtained using acoustic and NMR methods, which was attributed to different temperature measurement conditions.

We propose a method for generation of long-living autonomous fireball-like objects via a pulse erosive discharge between tin alloy electrodes. The objects are similar to the natural ball lightning in some properties, in particular, they have high energy density and are capable to burn through thin metal foils. The dynamics of the objects are studied using high speed videorecording. During their lifetime the fireballs generate aerogel threads. The studies of their structure by scanning electron microscopy reveal the presence of tin oxide nanoparticles and nanowhiskers.

The usage of diglycylglycine (GGG) was proposed to improve the separation of the complexes of heavy metal ions with EDTA by capillary zone electrophoresis. The tripeptide can interact with the complexes in capillary and thereby acts as a complex selector. The influence of GGG on the electrophoretic behavior of ten metal complexes (Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Pb(II) and Bi(III)) was studied in an acidic media using a negative polarity voltage supply. Three modes were proposed for the implementation of the in-capillary complexation. An addition of the reagent to the phosphate buffer solution changes the migration order of the complexes thus enabling separation of Cr(III) from Zn(II) and Ni(II) and Co(II) from Cd(II) and Mn(II). It is possible to determine Fe(III) and Bi(III) complexes selectively in presence of the other heavy metal ions. An injection of separate zones of EDTA, metal ions and GGG doesn’t provide good separation. A consecutive injection of Me-EDTA and GGG zones leads to Cu(II) and Pb(II) separation. So, it is possible to determine four metal ions (Cu(II), Pb(II), Fe(III) and Bi(III)) simultaneously at 260 nm. Calibration graphs plotted in optimal conditions show linearity within the concentration range from 5·10 -6 to 5·10 ‑3 mol/dm 3 . Limits of detection were calculated to be from 0.05 mg/dm 3 for Pb(II) ions to 0.72 mg/dm 3 for Bi(III). The proposed technique was applied for the determination of copper, lead, iron and bismuth in some natural and industrial samples. Keywords: capillary zone electrophoresis, copper, lead, iron, bismuth, EDTA, diglycylglycine. (Russian) DOI: http://dx.doi.org/10.15826/analitika.2014.18.4.013 L.K. Neudachina, E.L. Lebedeva Federal State Autonomous Educational Institution of Higher Professional Education «Ural Federal University named after the first President of Russia B.N.Yeltsin» (UrFU) , Ekaterinburg, Russian Federation References 1. Vogt C., Klunder G.L. 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