Determination by MS-MS of 1,1-dichlorodimethyl sulfone from pulp mill bleach plant effluents in aquatic organisms

Gas chromatography (GC) with electron capture detection (ECD), GC combined with mass spectrometry (MS), GC with multi-stage mass spectometry (MS-MS), and direct inlet MS-MS have been used to determine 1,1-dichlorodimethyl sulfone (DDS) in aquatic organisms in the receiving waters outside a pulp mill bleach plant. Both GC-MS-MC and direct inlet MS-MS of tissue extracts of fish and mussel appear to be sensitive, selective, and rapid analytical techniques for the determination of DDS.     

多孔型固体二氧化氯释放动力学研究

考察了自然或酸性环境下多孔型固体二氧化氯释放动力学方程和释放速率。结果表明：吸附在多孔型固体中的二氧化氯在初期表面阶段释放属于一级反应，动力学方程为logc=-0.042t 1.5392;微孔阶段释放量于二级反应，动力学方程为1／c=0.013t 1/c0.释放过程属于化学解吸过程。     

Zur Kenntnis eines Halogenooxo-Cobaltats(III): Sr8Co6O15Cl4

On an Oxide Chloride of Co^III: Sr₈Co₆O₁₅Cl₄ Sr₈Co₆O₁₅Cl₄ was prepared for the first time by flux reaction. It crystallizes with tetragonal symmetry: space group D_4h¹⁷–I4/mmm; a = 3.927; c = 31.429 Å; Z = 1. Co³⁺ has different coordinations. One point position show CoO₆ octahedra, the other one has a CoO₅Cl surrounding. An oxygen deficit exhibit partly distorted square pyramids. Sr₈Co₆O₁₅Cl₄ is strongly related to Ba₈In₆O_17.5 or can be seen as Sr₄Co₃O_7.5Cl₂ as a variety of the Sr₄Ti₃O₁₀ type.     

Haloaldehyde polymers,XLIX: Analysis of linear bornyl oxide initiated,acetate endcapped chloral oligomers by potassium ionization of desorbed species mass spectrometry

Linear chloral oligomers initiated with lithium bornyl oxide and acetate endcapped were analyzed by potassium ionization of desorbed species (K⁺ IDS) mass spectrometry. Using this technique we observed ions resulting from the [unimer]K⁺ with a mass of 381 daltons, to the [hexamer]K⁺ with a mass of 1 119 daltons. Furthermore, analysis of the isotope pattern supported our structural assignment. The individual lower oligomers were also investigated by GC and NMR spectroscopy.Previous paper in this series: Haloaldehyde Polymers XL VIII. W. J. Simonsick Jr., K. Hatada, Fu Xi, and O. Vogl [27]     

激光引发的氯自由基与1，2-二氯乙烷的反应研究

1,2-二氯乙烷裂解反应是一个自由基链反应。在热反应中,为了克服引发自由基反应所需要的能量,反应必须在较高温度下进行。但是在光化学反应中,特别是应用了激光引发自由基,使得这一裂解反应可以在较低的温度下进行。因此利用激光引发的自由基链反应,不仅在理论上有浓厚的兴趣,并且在工业上有广阔的应用前景。Wolfrum曾详细地研究过利用准分子激光(KrF激光)裂解1,2-二氯乙烷的反应。由于1,2-二氯乙烷对KrF激光有较强的吸收,容易产生氯自由基,使整个链反应速率决定步骤由链的引发变为链的传递,而降低反应温度。因为光化学反应温度低,抑止了很多副反应,从而提高反应的选择性。     

Application of an amperometric sensor to in-line monitoring of pulp bleaching with chlorine dioxide

Chlorine dioxide is replacing chlorine as the active compound in pulp bleaching in order to reduce the amount of chlorine used in the process and hence also in the waste waters. In bleaching with chlorine dioxide part of the effective bleaching chemical is usually chlorite. The electrochemistry of chlorine dioxide and chlorite at solid electrodes was studied by cyclic voltammetry at different pH values. The observed voltammograms indicated that reduction of chlorine dioxide gives chlorite and oxidation of chlorite gives chlorine dioxide. Both voltammograms were well developed, indicating a reversible process. Both platinum and glassy carbon were used as the working electrode. The dependence of the limiting current of chlorine dioxide and chlorite on pH was studied at both electrodes. The method was tested in the chlorine dioxide bleaching stage D1 in a typical bleaching process. A good correlation was found between the concentrations of chlorine dioxide and chlorite measured by the in-line amperometric method and a standard titrimetric method.     

Gas diffusion sequential injection system for the spectrophotometric determination of free chlorine with o-dianisidine

A gas diffusion sequential injection system for spectrophotometric determination of free chlorine is described. The detection is based in the colorimetric reaction between free chlorine and a low toxicity reagent o-dianisidine. A gas diffusion unit is used to isolate free chlorine from the sample in order to avoid possible interferences. This feature results from the conversion of free chlorine to molecular chlorine (gaseous) with sample acidification. With minor changes in the operating conditions, two different dynamic ranges were obtained enhancing the application both to water samples and bleaches. The results obtained with the developed system were compared to the reference method, iodometric titration and proved not to be statistically different. A detection limit of 0.6 mg ClO⁻/L was achieved. Repeatability was evaluated from 10 consecutive determinations being the results better than 2%. The two dynamic ranges presented different determination rates: 15 h⁻¹ for 0.6-4.8 mg ClO⁻/L (water samples) and 30 h⁻¹ for 0.047-0.188 g ClO⁻/L (bleaches).     

Purification of CH3Cl from CH3I using cold trap with sealed 2,2,4-trimethylpentane for δCl measurement

A cryogenic separation method of chloromethane (CH₃Cl) from methyl iodide (CH₃I) for δ³⁷Cl measurement with isotope ratio mass spectrometer is described. A cold trap with sealed 2,2,4-trimethylpentane (TMP) as the cryogen is used in this method. CH₃Cl can be separated from CH₃I at the TMP melting point (−107 °C) based on the difference in the vapor pressure between CH₃Cl (322.6 Pa) and CH₃I (lower than 1.3 Pa) at −107 °C. After two-step separation processes, the yields of CH₃Cl purified from CH₃Cl-CH₃I mixture are 96-101%, and the difference between the δ³⁷Cl_original and δ³⁷Cl_{After separation} is from −0.06 to +0.06‰ (0.01 ± 0.04‰). These results suggest that CH₃Cl is completely separated from CH₃I with no change of δ³⁷Cl value. This method using the cold trap with sealed TMP is very safe and not harmful, because the liquid organic compound used as the cryogen is contained in the trap and does not evaporate during the separation procedure. This method is also simple and inexpensive relative to the method using a gas chromatograph.     

Structural effects in low temperature radioluminescence of aqueous ionic systems

Structural effects in the radioluminescence spectra of glassy and polycrystalline aqueous solutions of chloride and alkaline ices observed by pulse radiolysis at temperatures 6–110 K are reported. The luminescence efficiency as well as position of λ_max of the emission spectra are dependent on the physical state and temperature of the matrix. For all the investigated aqueous polycrystalline matrices and for H₂O ice, the emission band peaking at about 330 nm, assigned to OH*A²Σ→X²Π transition appears at temperatures below 40 K. This UV band was not observed for glassy matrices. Luminescence bands observable in the visible range of spectrum (400–600 nm) can be associated with the emission of (OH⁻)*, the radiative capture of trapped electrons e⁻_t by metal cations Me⁺(Me²⁺) and trapped atoms H√_t. For polycrystalline chloride matrices a contribution of the emission of (Cl²⁻₂)* must be taken into account.