Determination of 8 Diuretics and Probenecid in Human Urine by Gas Chromatography-Mass Spectrometry: Confirmation Procedure

A fast and sensitive method for determination of 8 diuretics (acetazolamide, bendroflumethiazide, bumetanide, chlorthalidone, furosemide, hydrochlorothiazide, metolazone, triamterene) and masking agent (probenecid) in human urine using gas-chromatography with mass spectrometric detection is described. The extraction of the substances as function of the nature of organic solvent, mixing time and pH of aqueous phase was studied. The tandem mass spectrometry was used to increase selectivity of diuretics determination due to elimination of background interferences. Fragmentation reactions were studied for each compound and their collision energies were optimized to obtain the best selectivity. The results of method’s validation demonstrate its suitability in routine analysis for confirmation purposes.

New Method of Generation of Carbon Molecules and Clusters

Firstly the method of joint synthesis of carbon molecules and their hydrides is developed. The stage of high-temperature sublimation of carbon in a new method of generation of carbon molecules is completely excluded. By mass spectrometric method the condensation products of new method of pyrolysis (NMP) benzene are studied. Firstly clusters (C3-C17), typical for carbon vapour, in substances obtained under pyrolysis of hydrocarbons were detected. Fullerene C60 and its hydrides, quasi-fullerenes C48 and C33 inproducts of benzene pyrolysis are detected also. Firstly it is shown what clusters C3-C5 can be generated at so low (100?C-200?C) temperatures of decomposition of substance. Obtained experimental results firstly demonstrate that the small carbon molecules can be generated in reactionary conditions excluding evaporation of carbon. Dehydrogenation and destruction of hydrocarbon molecules is the first stage on a route of the transformation of benzene to carbon molecules.

Study of Thermolysis of Hydrogenated Carbon Molecules as Products of Fullerenization of Benzene, Xylene, Ethanol and Pyridine

Novel essentially distinct from already known (methods of hydrogenation of fullerenes (C60 and C70) or fullerite) method for the synthesis of highly hydrogenated carbon molecules is developed;such approach is perspective hydrogen capacity accumulators. First, the reactionary conditions are created for the realization of the process of fullerenization as direct transformation of molecules of aromatic hydrocarbons, pyridine and ethanol into carbon molecules, fulleranes (С60Н8-С60Н60 and С70Н8-С70Н44) and quasi-fulleranes (CnHn-6-CnHn-2 (n = 20 - 46)) containing up to 5.7 wt% hydrogen. X-ray amorphous powders of hydrogenated carbon molecules in gram amounts are obtained. Appreciable dehydrogenation of such samples of fulleranes and quasi-fulleranes at ~50&degC is began, while dehydrogenation of synthesized from fullerene (or fullerite) fulleranes is observed only at temperatures above 400&degC. Methods of NMR, IR spectroscopy, mass spectrometry MALDI and temperature-programmed desorption mass spectrometry EI are used for the study of condensed products of fullerenization of precursors molecules.

A simple description of the temperature dependence of the width of the fission-fragment mass yield in ^(197)Au and ^(209)Bi at intermediate energies

A simple approach is proposed to describe the experimental data for the widths of the fission-fragment mass yields in^(197)Au and^(209)Bi at low and intermediate energies.The approach is based on the expressions for the temperature dependence of the width of the fission-fragment mass yield and the mass of the most probable fragment.The expression for the width of the fission-fragment mass yield depends on the mass of the most probable fragment,the surface terms of the energy level density parameter,the temperature and the stiffness parameter of the potential related to mass-asymmetric degree of freedom.It is shown that the contribution of the surface term of the energy level density parameter is important for describing the experimental data in a wide range of energies.

Production of super-heavy nuclei in cold fusion reactions

A model for cold-fusion reactions related to the synthesis of super-heavy nuclei in collisions of heavy projectile-nuclei with a ^(208)Pb target nucleus is discussed.In the framework of this model,the production of the com-pound nucleus by two paths,the di-nuclear system path and the fusion path,are taken into account simultaneously.The formation of the compound nucleus in the framework of the di-nuclear system is related to the transfer of nucle-ons from the light nucleus to the heavy one.The fusion path is linked to the sequential evolution of the nuclear shape from the system of contacting nuclei to the compound nucleus.It is shown that the compound nucleus is mainly formed by the fusion path in cold-fusion reactions.The landscape of the potential energy related to the fusion path is discussed in detail.This landscape for very heavy nucleus-nucleus systems has an intermediate state,which is linked to the formation of both the compound nucleus and the quasi-fission fragments.The decay of the intermediate state is taken into account in the calculation of the compound nucleus production cross sections and the quasi-fission cross sections.The values of the cold-fusion cross sections obtained in the model agree well with the experimental data.