Hydroxyl emission at high latitudes

Intensity and rotational temperature of hydroxyl emission at high latitudes during winte

Twilight helium emission at high latitudes

Twilight helium emission at high latitudes during winte

Questions of Justification of State Policy Regulation of Production and Consumption of Socially Dangerous Goods and Services

The purpose of the study is to substantiate a reasonable balance between the interests of consumers and different segments of society in the process of production and consumption of socially dangerous goods and services and to develop recommendations for improving state policy in this area. Various points of view on the solution of the problem are analyzed. Possible options of further strategy of regulation of consumption of this group of goods and services on the example of tobacco products are considered. The methods and mechanisms of regulation that ensure both the protection of public health and the rights of consumers are characterized

Stripping-voltammetric determination of transition metals using electrodes modified by azacrown compounds

Voltammetric properties of macrocyclic complexes of transition metals are studied by using a carbon-paste electrode modified by diaza-18-crown-6, Cyclam, and their derivatives. A selective stripping-voltammetric procedure is proposed for determining Ni(II) and Co(II) with a carbon-paste electrode modified by Cyclam and its derivatives. To improve the sensitivity and selectivity of analysis, it is suggested that metal ions be preconcentrated at the surface of the modified electrode by using a 0.1 M NaCl solution as a supporting electrolyte with the following recording of voltammograms in the range from -0.3 to 0.8 V in a 0.1 M KOH solution. The detection limits for Ni(II) and Co(II) are 4 × 10-8 and 1.2 × 10-7 M, respectively. © 1996 MAEe Cyrillic signK Hayκa/Interperiodica Publishing

Extraction of inorganic and organic substances from aqueous solutions as host-guest complexes by vaseline oil containing crown compounds

Extraction of some metal ions and biologically active organic compounds as host-guest complexes from aqueous phase by solutions of crown compounds in Vaseline oil was studied. The same extraction systems were studied using the extractant as a constituent of a carbon paste electrode. The conditions ensuring the maximum extraction capability of Vaseline oil in the presence and absence of crown compound were found. © 1996 MAEe cyrillic signK Hayκa/Interperiodica Publishing

Stripping-voltammetric determination of transition metals using electrodes modified by azacrown compounds

Voltammetric properties of macrocyclic complexes of transition metals are studied by using a carbon-paste electrode modified by diaza-18-crown-6, Cyclam, and their derivatives. A selective stripping-voltammetric procedure is proposed for determining Ni(II) and Co(II) with a carbon-paste electrode modified by Cyclam and its derivatives. To improve the sensitivity and selectivity of analysis, it is suggested that metal ions be preconcentrated at the surface of the modified electrode by using a 0.1 M NaCl solution as a supporting electrolyte with the following recording of voltammograms in the range from -0.3 to 0.8 V in a 0.1 M KOH solution. The detection limits for Ni(II) and Co(II) are 4 × 10-8 and 1.2 × 10-7 M, respectively. © 1996 MAEe Cyrillic signK Hayκa/Interperiodica Publishing

Electrochemical Oxidation of Azacrown Transition Metal Complexes on a Graphite Electrode

Azacrown compounds and their 3d-transition metal complexes undergo oxidation on a graphite electrode in aqueous and organic solutions. The macrocyclic ligands are oxidized to radical cations which are involved in further electrode reactions. The one-electron oxidation of diazabenzo-18-crown-6 and triazabenzo-18-crown-6 is reversible. Diaza-18-crown-6, as well as cyclam and its derivatives are oxidized irreversibly and at more positive potentials. The central atom in the species resulting from the oxidation of the Co(II), Ni(II), and Cu(II) complexes has the oxidation state 3+. The voltammetric characteristics of the oxidation of the macrocyclic complexes are solvent-dependent

Stripping-voltammetric determination of some amino acids on a carbon-paste electrode modified by crown ethers

A method for detecting sulfur-containing amino acids on a carbon-paste electrode modified by dibenzo-18-crown-6 or dibromodibenzo-18-crown-6 ethers is developed. The selectivity of the method is accounted for by a specific interaction between crown ethers (modifying agents) and protonated amino groups of organic molecules of the analyte adsorbed by the surface of the modified electrode as a host-guest complex. The determination limits (clim) of cysteine, homocysteine, and glutathione are equal to (2-5) x 10-8 M. © 1997 MAEe Cyrillic signK Hayκa/Interperiodica Publishing

Stripping voltammetry of biologically active organic compounds as host-guest complexes at electrodes modified with crown ether

Procedures for determining the biologically active organic compounds Ioxynil, Prefix, Sayfos, Cythioate, and Karbation by stripping voltammetry using carbon-paste electrodes modified with dibenzo-18-crown-6 (DB18C6) or dibromo-DB18C6 crown ether were developed. The selectivity and sensitivity were improved by using a preconcentration of organic molecules as host-guest complexes at the electrode. The pesticide content was monitored by the oxidation peaks of Karbation and Ioxynil and by the peak current corresponding to the formation of mercury mercaptide for the S-containing compounds. The determination limits of the procedures suggested are 4.0 × 10-9,4.6 × 10-7, 3.8 × 10-8, 8.0 × 10-8, and 9.0 × 10-8 M for the pesticides Karbation, Prefix, Ioxynil, Sayfos, and Cythioate, respectively. © 1998 MAEe Cyrillic signK Hayκa/Interperiodica Publishing