Roentgenoluminescence of hexahydrate of uranyl nitrate in phosphoric acid solution

The fluorescence (FL) and roentgenoluminescence (XRL) spectra of yellow aqueous solution of hexahydrate of uranyl nitrate phosphoric acid solution have been measured. The XRL spectrum was compared with the XRL of the green alkali alumino-phosphate glasses doped with uranium. It was shown that both the FL and XRL were due to uranyl groups. The radiative transitions are ascribed to³_1u ¹ _g ⁺ .     

Mercury Speciation in Fish by High-Performance Liquid Chromatography (HPLC) and Post-Column Ultraviolet (UV)-Photochemical Vapor Generation (PVG): Comparison of Conventional Line-Source and High-Resolution Continuum Source (HR-CS) Atomic Absorption Spectrometry (AAS)

An ultraviolet-photochemical generator (UV-PVG) capable of post-column on-line transformation of both organic and inorganic mercury species to cold vapor (Hg⁰) with subsequent detection by quartz tube-atomic absorption spectrometry (QT-AAS) was developed. Mercury(II), methylmercury(I), ethylmercury(I), and phenylmercury(I) were successfully detected after separation by reversed-phase high-performance liquid chromatography (RP-HPLC). Two types of AAS detectors were compared. The first was a commonly used line-source instrument while the second was a high-resolution continuum source (HR-CS) AAS. The latter provided better limits of detection: 0.47?µg?L^?1 for Hg(II), 0.84?µg?L^?1 for methylmercury(I), 0.80?µg?L^?1 for ethylmercury(I), and 2.0?µg?L^?1 for phenylmercury(I). The repeatability at 30?μg?L^?1 was 3.6%, 4.1%, 6.2%, and 4.5% for these species (n?=?10). These figures of merit were comparable with those reported for more sensitive atomic fluorescence spectrometry. Nine sample extraction procedures were investigated. Extraction by tetramethylammonium hydroxide and HCl at 75?°C was selected as the only method compatible with the proposed separation and detection steps providing high extraction efficiency and no changes in mercury speciation. The applicability of the proposed high-performance liquid chromatography–ultraviolet-photochemical vapor generation–quartz tube-atomic absorption spectrometry method was demonstrated using fish samples and certified reference materials (CRM) DOLT-4 (dogfish liver) and ERM-CE464 (tuna fish). The results were comparable to those obtained by a reference method based on L-cysteine extraction and high-performance liquid chromatography–inductively coupled plasma-mass spectrometry (HPLC–ICP-MS) determination.     

Absorption properties of körbl-catalyst and manganese dioxide

Summary Körbl-catalyst and manganese dioxide absorb chlorine and bromine quantitatively at room temperature. This property is applied to simultaneous microanalytical determination of carbon, hydrogen and chlorine or bromine in compounds containing carbon, hydrogen, oxygen, chlorine or bromine, but not nitrogen or sulphur.

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Zusammenfassung Der Körbl-Katalysator und Mangandioxid absorbieren Chlor und Brom bei Raumtemperatur quantitativ. Sie wurden daher zur gleichzeitigen Bestimmung von C, H sowie Cl oder Br in Verbindungen verwendet, die C, H, O, Cl (oder Br), nicht aber N oder S enthalten.

     

On the behaviour of cerium(III) in hydrochloric acid

Summary The sorption of Ce³⁺ from hydrochloric acid and its chromatography on a column filled with Dowex 50 X8 was studied. The break-through volumes and elution volumes, together with the sorption profile and band broadening were determined at different temperatures and are discussed. The Chromatographic results are interpreted in terms of cerium complex formation.

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Über das Verhalten von Cerium(III) in salzsaurer Lösung

Zusammenfassung Die Sorption von Ce³⁺ aus salzsaurer Lösung in einer mit Dowex 50 X8 gefüllten Säule sowie dessen Chromatographie wurden untersucht. Die Durchbruchs- und Elutionsvolumina wurden bestimmt und diskutiert. Die Ergebnisse wurden im Sinne einer Komplexbildung interpretiert.

     

Application of a chemometric method for simultaneous determination of acetaminophen and diclofenac in content-uniformity and drug-dissolution studies

A new, repeatable, and rapid method has been developed for resolution of binary mixtures of acetaminophen and diclofenac with minimum sample pretreatment and without separation of the analytes. The method, based on the PLS1 processing of absorbance data in the UV region, was successfully used for quantification of the drug content of three tablet preparations. The results obtained were in good agreement with HPLC recovery data. The method also enabled determination of drug-dissolution profiles of these commercial tablets, by simultaneous determination of both analytes during the dissolution test.     

A two-step supercritical fluid extraction of polycyclic aromatic hydrocarbons from roadside soil samples

A two-step procedure for the supercritical fluid extraction (SFE) of polycyclic aromatic hydrocarbons from soil samples was developed. The procedure consists of a static supercritical fluid treatment in a closed extraction cell at a high temperature (T=250 or 340degreesC for 20 min) and an SFE with a solvent trapping. During the static phase, the sample is exposed to a supercritical organic solvent (methanol, toluene, dichloromethane, ACN, acetone, and hexane). The solvent penetrates particles of the matrix to substitute strongly bonded molecules and dissolves the analytes in the supercritical phase. At ambient temperature, supercritical fluids became liquid and lost their solvation abilities. Most of the analytes condense on the surface of the particles or on the extraction cell walls without forming strong bonds or penetrating deep into the matrix. Thus, the pretreatment liberates the analytes and they behave similar to those in freshly spiked samples. The common SFE with toluene-modified CO2 as an extraction fluid follows the static phase. With the use of the most suitable extraction phases (toluene, ACN), the extraction efficiency of the combined procedure is much higher (approximately100%). The results of the combined procedure are compared to the SFE procedure of the same untreated sample (difference less than 5%) and to the Soxhlet extraction. The extracts were analyzed using a GC with the flame ionization detection.     

Spectrophotometric determination of chloride in non-polar media by the mercury(II) thiocyanate reaction

A simple, rapid and accurate method for the spectrophotometric determination of chloride in non-polar media is described. The method is based on the well-known reaction of mercury(II) thiocyanate with chloride to release thiocyanate, which then reacts with iron(III). The optimum concentrations of reagents for the determination of chloride in 2,2,4-trimethylpentane (iso-octane) and cyclohexane are reported. The molar absorptivity of the complex at 505 nm is 5120 ± 200 dm³ mol^?1 cm^?1 for iso-octane and 5340 ± 340 dm³ mol^?1 cm^?1 for cyclohexane. Beer's Law is obeyed in the range 2 × 10^?7–2 × 10^?5 mol dm^?3 (0.01–1 mg l^?1) chloride.     

The Fe2+ chelate of hydrazinecarboxylic acid studied by the Mössbauer effect

The chelate compounds K[Fe(hyc)₃] and N₂H₅[Fe(hyc)₃]·H₂O (hyc = N₂H₃COO) were studied by the Mössbauer effect of ⁵⁷Fe at various temperatures. At room temperature the quadrupole splitting parameter is 2.77 mm/sec for K[Fe(hyc)₃] and 2.35 mm/sec for N₂H₅[Fe(hyc)₃]·H₂O, and the center shift is 1.08 mm/sec for both compounds. The temperature dependences of the quadrupole parameters yielded the crystal field splittings of the ⁵T_2g levels of the Fe²⁺ ions which indicate large trigonal distortion of the Fe(hyc)₃ anion. Using a molecular crystal-like treatment of the ferrous ion vibrations the temperature dependence of the recoilless fraction gave an effective Debye temperature Θ_D = 71°K for K[Fe(hyc)₃] and Θ_D = 90°K for N₂H₅[Fe(hyc)₃]·H₂O. No evidence for magnetic ordering was found down to 4.5°K in either compound.     

On path integrals and relativistic quantum mechanics

A proposal for formulation of relativistic quantum mechanics in terms of path integrals is presented.We are deeply indebted to Dr. M.Petrá for many stimulating discussions.     

Some physical properties of KCl+Pb2+ crystals

This paper presents the results of measurements of the mechanical and electrical properties of as-received pure and lead-doped crystals of potassium chloride. The critical resolved shear stress of the crystals obeys the Franks relationship in the whole concentration range. In addition, the correlation between ₀ and the Vickers hardness numberH was found and the equation is of the form ₀=k (H–H ₀). The solubility of Pb²⁺ in as-received KCl crystals was observed, from measurements of the electrical conductivity, to be low—the successive saturation of the solid solution started already in an environment of 5 mole ppm in agreement with data from the mechanical measurements. The density of cation vacancies and their mobility were represented by the following euqations ₁ T=6·25×10⁴ exp(–·75/kT) cm² K/volt. sec,n ₁=6·95×10²³ exp(–2·12/kT) vacancies/cm³ The value of 0sd46±0·02 eV was found as a rough estimate of the association energy.The authors wish to express their thanks to Professor Dr. J. Z.Damm and Ing. E.Mariani for their stimulating interest in the present work.