A method of obtaining highly dispersed tin (II) oxide (SnO) powder by the evaporation-condensation method was investigated when the initial material was heated by focused radiation of a subterahertz gyrotron with a frequency of 0.26 THz and a power of 1 kW. The process was carried out with a purge with nitrogen inert with respect to SnO. A powder with a SnO weight content of 92% was obtained. The specific surface was 7.20 m2/g, which corresponds to an average particle size of 130 nm. The characteristics of the obtained powder are analyzed. The applicability of the experimental setup for the production of nanopowders from compounds requiring special gas conditions during the evaporation-condensation process has been demonstrated.

A method for the preparation of a highly dispersed powder of tin monoxide (SnO) by the evaporation/condensation method under heating the initial material with focused radiation of a subterahertz gyrotron with a frequency of 0.26 THz and a power of 1 kW is investigated. The process is carried out with a purge with nitrogen that is inert with respect to SnO. A powder with a SnO content of 92 wt % is obtained. The specific surface area of the powder is 7.20 m 2 /g, which corresponds to an average particle size of 130 nm. The characteristics of the obtained powder are analyzed. The applicability of the experimental setup for the production of highly dispersed powders from compounds that require special gas conditions in the evaporation/condensation process is demonstrated.

A technique for imaging of high-power millimeter-wave (MMW) beams using visible light emission from a surfaceinitiated microwave gas breakdown is discussed. A wave beam from pulsed 250 GHz gyrotron was imaged using a microwave gas breakdown initiated by a surface of a metal-dielectric screen. The screen was placed in a shallow metal chamber filled with helium with an admixture of argon. In the region, where MMW intensity was higher than the threshold intensity of the surface-initiated microwave gas breakdown, the intensity profile of a high-power MMW beam, which was obtained using this technique, was in good agreement with the data obtained using the thermographic technique.

The purity of different industrially produced extractants, such as hexane, n-octane, carbon tetrachloride, and ethanol, was studied using gas chromatography-mass spectrometry and gas chromatography. It was shown that the most characteristic impurities in these extractants were volatile organochlorine compounds ( LHS ) and hard volatile esters of o-phthalic acid ( o -phthalates ). The impurity content of these substances in extractants could reach tens of mg/l. Based on the calculation of the distribution coefficients of impurities in the “liquid-vapor” system, the methods of Rayleigh distillation and rectification were proposed for removing the impurities from the extractants. Gas chromatographic mass spectrometric and gas chromatographic analysis of purified extractants showed that the effective removal of impurities of o-phthalic acid esters was possible using the Rayleigh distillation during the distillation of extractants at an evaporation rate of no more than 6·10 –4 ml·cm –2 ·s –1 . This allowed obtaining a volume of extractant enough to carry out 50-55 microextractions in 5 minutes. The effective removal of volatile LHS was achieved by a multi-stage distillation method - rectification. The concentration of impurities of the investigated substances in the purified extractants did not exceed 10 –3 –10 –5 mg/l. The liquid-phase microextraction preconcentration with the use of purified extractants decreased the detection limits of LHS and o-phthalates in the water to 2∙10 -7 -1∙10 -5 and 4·10 -6 ‒1·10 -5 mg/l, respectively. Keywords: microextraction preconcentration, rectification, Rayleigh distillation, detection limits, extractant, gas chromatography, gas chromatography mass spectrometry (Russian) DOI: http://dx.doi.org/10.15826/analitika.2019.23.1.008 V.A. Krylov 1 , P.V. Mosygin 1 , L.V. Smirnova 1 , S.A. Bulanova 1 , I.A. Zhituhina 1 , G.V. Pushkarev 2 1 N.I. Lobachevsky Nizhny Novgorod State University, Russian Federation, 603950, Nizhny Novgorod, Gagarin pr., 23 2 Joint –Stock Company «Scientific - Production Enterprise «Salyut», Russian Federation, 603950, Nizhny Novgorod, Larina Str., 7

The purity of different industrially produced extractants, such as hexane, n-octane, carbon tetrachloride, and ethanol, was studied using gas chromatography-mass spectrometry and gas chromatography. It was shown that the most characteristic impurities in these extractants were volatile organochlorine compounds ( LHS ) and hard volatile esters of o-phthalic acid ( o -phthalates ). The impurity content of these substances in extractants could reach tens of mg/l. Based on the calculation of the distribution coefficients of impurities in the “liquid-vapor” system, the methods of Rayleigh distillation and rectification were proposed for removing the impurities from the extractants. Gas chromatographic mass spectrometric and gas chromatographic analysis of purified extractants showed that the effective removal of impurities of o-phthalic acid esters was possible using the Rayleigh distillation during the distillation of extractants at an evaporation rate of no more than 6·10 –4 ml·cm –2 ·s –1 . This allowed obtaining a volume of extractant enough to carry out 50-55 microextractions in 5 minutes. The effective removal of volatile LHS was achieved by a multi-stage distillation method - rectification. The concentration of impurities of the investigated substances in the purified extractants did not exceed 10 –3 –10 –5 mg/l. The liquid-phase microextraction preconcentration with the use of purified extractants decreased the detection limits of LHS and o-phthalates in the water to 2∙10 -7 -1∙10 -5 and 4·10 -6 ‒1·10 -5 mg/l, respectively. Keywords: microextraction preconcentration, rectification, Rayleigh distillation, detection limits, extractant, gas chromatography, gas chromatography mass spectrometry (Russian) DOI: http://dx.doi.org/10.15826/analitika.2019.23.1.008 V.A. Krylov 1 , P.V. Mosygin 1 , L.V. Smirnova 1 , S.A. Bulanova 1 , I.A. Zhituhina 1 ,  G.V. Pushkarev 2 1 N.I. Lobachevsky Nizhny Novgorod State University, Russian Federation, 603950,  Nizhny Novgorod, Gagarin pr., 23 2 Joint –Stock Company «Scientific - Production Enterprise «Salyut»,  Russian Federation, 603950, Nizhny Novgorod, Larina Str., 7