Advanced Materials Research Vols. 554-556

Abstract: As being a vital role affecting the water quality and stimulating the circulation of pollution in native lake, the physicochemical properties of water and the surface sediments in Dianchi Lake dredging area were investigate to determine the level of physicochemical properties of the dredging area, and to evaluate the effects of dredging project. The results showed that the physicochemical properties indicated a more seriously polluted state in Caohai. The effectiveness of dredge work in Caohai was ignorable comparing to Waihai, but it was more obvious in the sediment than in water.

Abstract: The flotation separation and determination behaviours of mercury (Ⅱ) by sodium bromide -ammonium thiocyanide-octadecyl trimethyl ammonium bromide system were studied. The effects of different parameters,such as the dosages of NH₄SCN and octadecyl trimethyl ammonium bromide (OTMAB),various salts and acidity etc. on the flotation yield of Hg²⁺ have been investigated to select the experimental conditions.The results showed that in the presence of 1.0g NaBr and when the dosage of 0.1 mol/L NH₄SCN was 0.50 mL and 0.01 mol/L OTMAB solution was 1.00 mL respectively, the formed water-insoluble ternary association complex of (OTMAB)₂[Hg(SCN)₄] floated above water phase and liquid-solid phases were formed with clear interface. In this condition, Cd²⁺,Mn²⁺,Ni²⁺,Co²⁺,Fe²⁺ and Pb²⁺ could not be floated and Hg²⁺ could be floated quantitatively at pH2.0.Therefore, the quantitative separation of Hg²⁺ from the above metal ions could be achieved. A new method of determination of trace mercury by flotation separation was established.The proposed method has been successfully applied to the determination of Hg²⁺ in the sample of synthetic water and the flotation yield was 94.2%~97.9%.

Abstract: A high performance liquid chromatographic method has been developed for separation and quantitation of sucrose esters using charged aerosol detection (CAD) combined with mobile phase compensation. Two Acclaim120 C18 columns (75×3.0mm, 3μm) and the gradient composition (0 min – 72% A + 25% B + 3%C, 7.5 min – 75% A + 25% B + 3%C, 19.5 min – 97% A + 3%C, 30 min – 97% A + 3%C, where A is methanol, B is water and C is tetrahydrofuran) were applied. A precisely inverse gradient composition (0 min – 97% A + 3%C, 7.5 min – 97% A + 3%C, 19.5 min – 72% A + 25% B + 3%C, 30 min – 72% A + 25% B + 3%C) was also used. The mobile phase compensation was performed by mixing of the column effluent with the mobile phase of exactly reverse composition provided by a second pump before introduction into the CAD. Introduction

Abstract: To determine total arsenic in Chinese traditional herbs, a hydride generation atomic fluorescence spectrometry method was developed. The samples were pretreated by digesting system with HNO3-H2O2. The experimental conditions were studied and optimized. Under the optimum conditions, the samples was measured. There was a good linear relationship between the fluorescence intensity and arsenic concentration in the range of 0～80μg•L-1with a correlation coefficient of 0.9995,while the detection limit was 0.036μg•L-1,the relative standard deviation was 1.9% .Trace total arsenic in the samples was 0.145～0.376μg•g-1 and a recovery range of 83.9%～108.5% were obtained.

Abstract: On the basis of the quantitative structure-property relationship (QSPR) method and the quantum chemical descriptors including molecular van der Waals volume (Vmc), dipole moments (μ), the most negative formal charge in solute molecule (q-), and the most positive formal charge on a hydrogen atom in solute molecule (q+) of organic compounds, the values of activity coefficients at infinite dilution, , for 16 solutes in ionic liquid 1-ethyl-3-methylimidazolium diethylphosphate ([EMIM][DEP]) at 323.15 K were correlated with the descriptors. The result showed that the QSPR model had a good correlation and could successfully describe . The quantitative relationship between organic molecular structure and in [EMIM][DEP] was obtained and the correlation parameters were analyzed to understand the interactions that affect activity coefficients at infinite dilution.

Abstract: This thesis makes a research about the effect of the pH on dispersion and catalytic activity of γ-Al₂O₃. The characterization of catalytic uses the reaction of Hydrogenation of nitrobenzene, ASS and HOT etc. The results show that the impregnating solution’s pH has great effect on the dispersion of catalytic active components but no effect on catalytic activity.

Abstract: Sulfhydryl lignin was prepared by immobilizing sulfhydryl onto wood lignin. The effect of pH, temperatμre, adsorption time, salinity of condiment and amino acid concentration of condiment on the adsorption behavior of sulfhydryl lignin was investigated, respectively. The adsorption kinetics and thermodynamics of Cu(Ⅱ) were also studied.

Abstract: Components of burned gasoline was analyzed by Gas Chromatography Mass Spectrometry (GC-MS) in this article. The results show that sample of burned gasoline contains 28 kinds of components, Groups of characteristic compounds and distribution of components were obtained in the gasoline. Pattern recognition was useful for the detection and characterization of gasoline residues.

Abstract: The properties of polyflavonoid tannins from the mangrove species depend on their structure in terms of monomer units, their mean degree of polymerization and the linkage-type between flavan-3-ol units with a considerable range of structural variation. Polyflavonoid tannins were characterized by matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS), which were too difficult to be resolved by other techniques. MALDI-TOF mass spectra of polyflavonoid tannins of four mangrove species in Rhizophoraceae, Kandelia candel, Ceriops tagal, Bruguiera cylindrica and Rhizophora apiculata showed as follows: (1) procyanidin oligomers formed by catechin/epicatechin, and catechin-3-O-rhamnoside monomers were present in great proportions; epigallocatechin and epicatechin gallate monomers were not detected; (2) the doubly linked structure of A-type procyanidins were also evident from the mass spectra of K. candel; (3) there were major differences in polyflavonoid tannin structure among mangrove species; and (4) the distribution of tannin oligomers, and the number-average degree of polymerization obtained by MALDI-TOF MS appeared to compare well with the results obtained by 13C nuclear magnetic resonance (NMR) analysis.

Abstract: In order to eliminate the temperature lag effect and obtain the accurate temperature results from hyper differential scanning calorimetry (Hyper-DSC) operated at high heating rate, an adjustable method, namely “Extrapolation Method”, had been introduced by us in former papers. And in this paper, we wanted to support the accuracy of this method by other instruments. Specifically, the extrapolated glass transition temperatures (Tg, 61.5 °C) of PLA film, which was obtained by Hyper-DSC, was close to the value detected directly by normal DSC (62.0 °C). And the extrapolated Tg of waxy starch film (59.7 °C for 8.7% moisture content, and 57.2 °C for 11.2% moisture content) was close to the values detected by modulated temperature DSC (MT-DSC) (63.6 °C and 56.8 °C correspondingly). Consequently, these experimental results support that the “Extrapolation Method” is a feasible way to eliminate temperature lag effect for Hyper-DSC.