Determination of Phenol in Surface Waters by High-Performance Liquid Chromatography with Sorption Preconcentration

The retention of phenol and its derivatives on Silasorb C₈ and PepRPC ^TMHR 5/5 was studied. Both columns are suitable for the separation of pyrocatechol–phenol–o-cresol(p-cresol)–2,6-xylenol mixtures using mobile phases containing 10–20 vol % of isopropanol and 1% glacial acetic acid in water. A procedure was developed for determining phenol with a detection limit of 4 mg/L (acetonitrile; signal-to-noise ratio, 2; loop volume, 25 L). With preconcentration from 1-L samples in a Diapak-phenol/P cartridge, the procedure allows phenol to be determined in water samples with a detection limit of 4 g/L. The procedure was used in analyses of samples of river and tap water.     

Terbium-containing copolymers based on the norbornene functional derivatives. Synthesis, photoluminescent and electroluminescent properties

New carbazole- and terpyridine- containing norbornene derivatives were synthesized and structurally characterized. On the basis of these compounds by the method of metathesis polymerization copolymers were obtained with carbazole and terpyridine fragments in side chains. The synthesized copolymers react with terbium pyrazolonate complex to form the terbium-containing polymeric materials exhibiting the metalcentered photo- and electroluminescence.     

X-ray spectral and photoelectron study of the electronic structure of copper phthalocyanine and its fluoro-substituted analog

A complex experimental study of Cu(2p _3/2), Cu(2p _1/2) photoelectron and Kα_1,2 and Lα_1,2 X-ray emission spectra of copper in copper phthalocyanine CuPcH₁₆ and its fluoro-substituted analog CuPcF₁₆ is carried out. A charge transfer model is used to interpret the spectra. It is shown that Kα₁ and Kα₂ lines of the spindoublet of copper have a complex structure due to the processes of metal-to-ligand charge transfer. The role of a satellite in the formation of emission lines is revealed.     

An X-ray absorption spectroscopy study of the electronic structure of copper phthalocyanine and its fluorosubstituted analog

An X-ray absorption spectroscopy study of the electronic structure of unsubstituted and hexadecafluoro-substituted copper phthalocyanines is performed. L absorption spectra of the copper atom and K absorption spectra of carbon, nitrogen, and fluorine atoms of unsubstituted and hexadecafluorosubstituted copper phthalocyanine are examined. A comparison of the absorption spectra in one binding energy scale enabled the estimation of contributions of AOs of all atoms of the considered compounds to lower unoccupied molecular orbitals and to determine the sequence of levels, their energies, and the occurrence of the interaction between certain atoms.     

Spectrophotometric determination of thiocyanate ions in stratal waters

The formation of [FeSCN]²⁺ complex in hydrochloric and sulfuric acid medium was studied by spectrophotometry using iron(III) sulfate and ammonium iron(III) sulfate solutions as reactants. A method for the determination of 10–200 μg SCN^? in 25 mL water solutions containing ammonium iron(III) sulfate in sulfuric acid medium was developed; its determination limit is 2.6 μg (P = 0.99, n = 9). The method was applied for the analysis of model water samples with macro- and micro-component compositions similar to that of water from the Arigol licensed area. Operational control of the accuracy rate was performed by the standard addition method. The developed method can be applied to analyze water samples containing 1–90 mg/L thiocyanate ions.     

A study of sodium diethyldithiocarbamate oxidation at glassy carbon electrode in water and water-organic mixtures

The oxidation of sodium diethyldithiocarbamate at a glassy carbon electrode in water and water-organic mixtures in the presence of KCl and NaOH is investigated. Using cyclic square-wave voltammetry and rotated electrode voltammetry it is shown that, in water and water-ethanol mixtures, the electrode reaction is irreversible. In the case of KCl water solution, the oxidation reaction involves one electron. In the case of KCl in a water-ethanol mixture, two electrons are involved. The possible oxidation mechanism is discussed.     

Flow effects in high-energy nucleus collisions with Ag(Br) in emulsion

Various flow phenomena observed by a unique emulsion method are reviewed. The experimental data of the emission of projectile and target fragments and relativistic particles in collisions of 1–160 A GeV/c ¹⁶O, ²²Ne, ²⁸Si, ³²S, ⁸⁴Kr, ¹⁹⁷Au, and ²⁰⁸Pb nuclei with ¹⁰⁸Ag (⁸⁰Br) targets are investigated. The transverse-momentum approach, the flow-angle analysis using principal vectors, the azimuthal correlation functions, the method of azimuthal correlations between charged secondaries, and the method of Fourier expansion of the azimuthal angle distributions are applied. Evidence of the directed flow of spectators has been obtained in the medium-impact nuclear interactions. In azimuthal distributions, with respect to the reaction plane, the signal of the elliptic flow of participants has been observed.     

A systematic study of the energy independent behaviour of the fragmentation regions in16O-Em interactions from 3.7 to 200A GeV

The scaling behaviour in the fragmentation regions is investigated for¹⁶O-Em interactions from 3.7 to 200A GeV. It is found that in both the projectile- and the target-fragmentation regions, the multiplicity and pseudo-rapidity distributions as well as the two-particle pseudo-rapidity correlations are independent of incident energy. The intermittency indices at 14.6, 60 and 200A GeV are the same within the experimental errors, indicating that the limiting fragmentation hypothesis works with regard to dynamical as well as statistical fluctuations.     

Reaction of ephedrine hydrochloride with sodium crosscarmellose and its account in the analysis of ephedrine-containing preparations

It is shown by HPLC and Fourier-transform IR spectrometry that ephedrine hydrochloride (EH) reacts with an auxiliary pharmaceutical substance, sodium crosscarmellose, in aqueous-organic solutions and in dry mixtures. This process may lead to the underestimation of the results of determining EH in the analysis of preparations containing these components. A probable mechanism of the reaction of EH with sodium cross-carmellose is considered, and possible techniques for eliminating its interfering effect are proposed.     

关于单位园周上阶梯函数的性质

Ｔ．Ｓｈｅｉｌ－Ｓｍａｌｌ［１］讨论了阶梯函数的Ｆｏｕｒｉｅｒ级数。本文对［１］中所涉及到一些阶梯函数的性质进行了详细讨论，并给出了详细证明。