摘要：
In this work, a novel method of combining solid phase extraction (SPE) with solidified floating organic drop microextraction (SFODME) was developed for the speciation of inorganic arsenic in wastewater samples by electrothermal vaporization inductively coupled plasma mass spectrometry. In the SPE step, titanium dioxide nanotubes were used for preconcentration of the analytes and removal of the inorganic and organic matrix from the wastewater samples. The elution solution from the SPE was employed for further preconcentration and separation of the analytes with SFODME. The main factors affecting the separation and determination of the analytes were also examined in detail. Under optimal conditions, the detection limits of this method were 0.073 and 0.089 pg mL-1 with relative standard deviations of 5.9% and 4.7% for As(III) and As(V) (n=9, c=1.0 ng mL-1), respectively. This method was successfully applied for the speciation of inorganic arsenic in industrial wastewater, urban sewage, and certified reference material of water sample without any pre reduction and pre-oxidation operation.
摘要：
Based on titanium dioxide nanofibers (TDNFs) as a new adsorbent for solid phase extraction (SPE), a method was developed for the determination of trace rare earth elements in biological and environmental samples by inductively coupled plasma mass spectrometry (ICPMS). The adsorption behaviors of the analytes on TDNFs were studied systematically. The effects of the experimental parameters, including pH, sample solution flow rate and volume, eluent concentration and volume, and interfering ions on the recoveries of the analytes, were examined in detail. Under the optimum conditions, the detection limits of this method ranged from 0.12 pg mL-1 (Lu) to 0.61 pg mL-1 (La), and the relative standard deviations (RSDs) for the determination of REEs were less than 4.5% (n=9, c=1.0 ng mL-1). The linear range of the calibration curve spanned four orders of magnitude. This method was validated using a certified reference material of tea leaves and successfully applied for the determination of trace light (La), medium (Eu), and heavy (Lu) rare earth elements in natural water samples with recoveries of 94.0-105%.
摘要：
In this work, a novel method was developed for the speciation of inorganic antimony by solidified floating organic drop microextraction (SFODME) and electrothermal vaporization inductively coupled plasma mass spectrometry (ETV-ICP-MS). Ammonium pyrroinedithiocarbamate (APDC) was used as both a chelating reagent in SFODME and a chemical modifier in ETV. Sb(III) could react with APDC to form complexes at pH 6.0, and the complexes were quantitatively extracted into the organic phase of 1-dodecanol, whereas Sb(V) remained as free species in the aqueous phase. Sb(III) was directly determined by ETV-ICPMS. Total Sb was determined by the same method after reducing Sb(V) to Sb(III). The concentration of Sb(V) was obtained by subtracting Sb(III) from total Sb. The main factors affecting the separation and determination were examined in detail. Under optimized conditions, the detection limits were 0.54 pg mL(-1) and 0.71 pg mL(-1) for Sb(111) and Sb(V), respectively. The relative standard deviations for Sb(111) and Sb(V) were 5.3% and 4.6% (c=1.0 ng mL(-1) n=9), respectively. This method was applied for the speciation of inorganic antimony in natural water samples and a standard reference material with satisfactory results.
摘要：
ZnBr2 supported on magnetic nanoparticles Fe3O4 coated by MCM-41 (Fe3O4@MCM-41/ZnBr2) was prepared and characterized by infrared spectroscopy (IR), powder X-ray diffraction (XRD) and nitrogen adsorption–desorption isotherms. The as-prepared samples were used as a recyclable catalyst for solvent-free synthesis of styrene carbonate (SC) from styrene oxide (SO) and carbonate dioxide (CO2). The results showed that Fe3O4@MCM-41/ZnBr2 exhibited similar catalytic activity to homologous ZnBr2. It was found that the reaction depended on the reaction conditions in terms of the yield of SC. The yield of SC at 81.5% was obtained with 8 MPa CO2 pressure at 90 °C for 3 h. The supported catalyst Fe3O4@MCM-41/ZnBr2 can be easily recovered by a permanent magnet after the reaction and reused without further treatment. No significant change in the structure and loss in activity were observed. The yield of SC changed in a small range from 79.2 to 82.6% during 5 cycles.
摘要：
In this work, a novel method was developed for the simultaneous determination of different volatile elements (refractory Cr, medium volatile Cu, and easily volatile Cd) in high purity zirconium dioxide (ZrO2) by in situ matrix removal and electrothermal vaporization inductively coupled plasma mass spectrometry (ETV-ICP-MS). A polytetrafluoroethylene slurry (PTFE) as a chemical modifier not only enhanced the difference in the volatility between the analytes and the matrix for in situ matrix removal, but also results in their similar vaporization behaviors of the different volatile elements (Cr, Cu, and Cd) for their simultaneous determination. Under optimum operating conditions, the detection limits (DLs) for Cr, Cu, and Cd were 2.5, 9.8, and 3.4 ng g(-1) with relative standard deviations (RSDs) of less than 6.2%, respectively. The calibration graphs of the analytes were linear over three orders of magnitude. This method was applied to the simultaneous determination of the different volatile elements Cr, Cu, and Cd in high purity ZrO2, and the results were in good agreement with those obtained by conventional pneumatic nebulization (PN) ICP-MS after separation of the matrix with a solvent extraction procedure.
摘要：
In this paper, a novel method was developed for the preconcentration, separation, and determination of light (Ce), medium (Eu and Gd), and heavy (Yb) rare earth elements (REEs) by inductively coupled plasma mass spectrometry (ICP-MS), based on the adsorption of Ce3+, Eu3+, Gd3+, and Yb3+ on carbon nanofibers (CNFs) loaded with 1-phenyl-3methyl-4-benzoyl-5-pyrazone (PMBP). The REEs can be adsorbed quantitatively on CNFs-PMBP in the pH range of 5.0 to 8.0 and then eluted completely with 1.0 mol L-1 HNO3. The experimental parameters for the preconcentration and separation of REEs, such as pH, sample flow rate / volume, eluent concentration / volume, and interfering ions, were examined in detail. Under optimum conditions, the detection limits of this method were found to be 1.5, 0.9, 0.5, and 0.3 pg mL(-1) for Ce, Eu, Gd, and Yb, respectively, and their relative standard deviations were less than 5% (c=1.0 ng mL(-1), n=9). This method has been applied to the determination of trace REEs in a natural water sample and a certified reference material, GBW 07602 (GSV-1) Combined Sample of Shrub Branch and Leaves, with satisfactory results.
摘要：
黄酮类物质具有优良的防腐抗菌效果,但从植物中提取和纯化技术尚不成熟,为此探讨了油竹干黄酮提取液的大孔树脂纯化工艺。通过7种不同型号大孔树脂对黄酮粗提液的吸附与解吸实验,优选出AB-8型大孔树脂;并得出油竹干黄酮提取液的最佳纯化条件为:1.0 mg/m L黄酮水溶液,上样液p H为6.0,上样速度为1.0 m L/min,最大上样量为170 m L;采用浓度为60%的乙醇进行洗脱,洗脱速度为1.5 m L/min,其用量为120 m L。此条件下纯化效果最佳,竹干黄酮样品纯度由21.3%提高到50.85%。
摘要：
The multi-porous ZnFe2O4 (ZFO) nanotubes are fabricated by the direct annealing process of ZFO precursor nanofibers, which is prepared by a facile electrospinning method. The crystal structure, composition, morphology, magnetic property, specific surface area and pore size distribution of multi-porous ZFO nanotubes are systematically characterized. The results indicated the multi-porous ZFO nanotubes with high purity phase possess obvious multi-porous and tubular microstructure, the mean inner diameter, specific surface area and pore volume are about 150 nm, 57.42 m(2) g(-1) and 0.16 cm(3) g(-1), respectively. Moreover, the multi-porous ZFO nanotubes exhibit a better photocatalytic activity than that of ZFO nanoparticles for photocatalytic degradation of RhB solution. (C) 2016 Elsevier B.V. All rights reserved.
摘要：
The inhibitive action of extract from mint leaves(EML) on Q235 A hot rolled carbon steel(HRCS) in 0.5mol/L H2SO4 solution was studied using weight loss measurement, electrochemical polarization and sc
