Quality analysis of herbal medicine products prepared from Herba sarcandrae by capillary electrophoresis with electrochemical detection

A capillary electrophoresis with electrochemical detection(CE-ED) method was developed for the quality analysis of herbal medicine products prepared from the same herb of Herba Sarcandrae: Fufang Caoshanhu tablets, Qingrexiaoyanning capsules, and Xuekang oral liquids. Under the optimal analysis conditions, the low detection limit[1.0x10(-7) mol/L(S/N=3)] and the wide linear range(1.0x10(-7)-1.0x10(-4) mol/L) were obtained for quality standard compound of isofraxidin. The precisions of the peak current and the migration time(as RSDs) for the real sample analysis were 2.0%-2.6%, and 1.2%-1.8% for isofraxidin, respectively.

Photochemical synthesis and self-assembly of gold nanoparticles

Colloidal gold was prepared by UV light irradiation of the mixture of HAuCl4 aqueous solution and poly(vinyl pyrrolidone) (PVP) ethanol solution in the presence of silver ions. The resulting sheet-like nanoparticles were found to self-assemble into nanoflowers by a centrifuging process. The results of control experiments reflected that only suitable size sheet-like nanoparticles could assemble into the flower-like structures. The presence of Ag ions and PVP are essential for the formation process of nanoflowers.

市售高丽参与中国红参的质量评价

目的:比较市售高丽参与中国红参中人参皂苷的含量,初步作出二者的质量评价。方法:采用比色法对市售高丽参与中国红参进行总皂苷含量测定,采用高效液相色谱法对高丽参与中国红参中主要单体皂苷进行测定比较。结果:中国红参总皂苷和主要的单体皂苷含量均高于韩国高丽参,而且红参中含有高丽参中不存在的单体皂苷Rg3、20S-Rg3。结论:市售中国红参质量高于市售高丽参。

Crystallographic and electrochemical characteristics of Ti-Zr-Ni-Pd quasicrystalline alloys

Ti45Zr35Ni20-xPdx (x = 0, 1, 3, 5 and 7, at%) alloys were prepared by melt-spinning. The phase structure and electrochemical hydrogen storage performances of melt-spun alloys were investigated. The melt-spun alloys were icosahedral quasicrystalline phase, and the quasi-lattice constant increased with increasing x value. The maximum discharge capacity of alloy electrodes increased from 79 mAh/g (x = 0) to 148 mAh/g (x = 7). High-rate dis-chargeability and cycling stability were also enhanced with the increase of Pd content. The improvement in the electrochemical hydrogen storage characteristics may be ascribed to better electrochemical activity and oxidation resistance of Pd than that of Ni.

Influence of metal particle size on the hydrogenation of maleic anhydride over Pd/C catalysts in scCO(2)

Hydrogenation of maleic anhydride (MAH) with Pd/C catalysts in supercritical carbon dioxide (scCO(2)) was investigated. The selectivity for gamma-butyrolactone (GBL) reached 97.3% in scCO(2) at 100% conversion of MAH, which was notably higher than that of 77.4% obtained in organic solvent of ethylene glycol dimethyl ether (EGDME). The particle size of Pd exhibited large influence on the reaction rate and selectivity of GBL. Higher selectivity of GBL was obtained with Pd/C catalyst of smaller Pd particle size, and the rate of GBL selectivity increase as a function of CO2 pressure was found to be significantly correlated with Pd particle size.

浊点萃取-石墨炉原子吸收光谱法测定环境样品中的镉

建立了浊点萃取分离富集石墨炉原子吸收光谱法测定环境样品中痕量镉的方法。浊点萃取选择8-羟基喹啉为螯合剂,Triton X-100为表面活性剂。在pH8～9、0.01%8-羟基喹啉和0.2%-Triton X-100、80℃水浴20 min的优化条件下,所建立方法的检出限为2.5 ng/L;加标回收率为94.6%～106.2%;对样品溶液进行富集的富集因子为17。利用该方法分别测定了2个实际水样和2个国家标准参考物质中的总镉含量,结果令人满意。

Synthesis and characterization of rigid-rod sulfonated polyimides bearing sulfobenzoyl side groups as proton exchange membranes

A novel wholly aromatic diamine, 2,2 '-bis(3-sulfobenzoyl)benzidine (2,2 '-BSBB), was successfully prepared by the reaction of 2,2 '-dibenzoylbenzidine (2,2 '-DBB) with fuming sulfuric acid. Copolymerization of 1,4,5,8-naphathlenetetracarboxylic dianhydride with 2,2 '-BSBB and 2,2 '-DBB generated a series of rigid-rod sulfonated polyimides. The synthesized copolymers with the -SO3H group on the side chain of polymers possessed high molecular weights revealed by their high viscosity and the formation of tough and flexible membranes. The copolymer membranes exhibited excellent oxidative stability and mechanical properties due to their fully aromatic structure extending through the backbone and pendent groups. They displayed clear anisotropic membrane swelling in water with negligibly small dimensional changes in the plane direction of the membrane. The proton conductivities of copolymer membranes increased with increasing IEC and temperature, reaching value above 1.25 x 10(-1) S/cm at 20 degrees C, which is higher than that of Nafion (R) 117 at the same measurement condition. They displayed reasonably high proton conductivity due to the higher acidity of benzoyl sulfonic acid group, the larger interchain spacing, which is available for water to occupy, taking their lower water uptake (WU) into account. Consequently, these materials proved to be promising as proton exchange membrane.

纳米GdPO_4:Eu~(3+)的制备、结构和发光特性

采用沉淀法,在不同pH值、EDTA二钠盐参加和不同温度等条件下制备出纳米GdPO4:Eu3+。利用X射线衍射,扫描电镜和荧光光谱等测试手段对制备的纳米GdPO4:Eu3+的结构,形貌和发光性能进行了研究。XRD和SEM研究结果表明:所有样品均为纯GdPO4相,纳米粒子的大小、形貌和晶面的发育与合成条件有关;发射光谱和激发光谱的研究结果表明:5D0-7FJ特征发射峰强度和激发光谱的强度随pH值和烧结温度的提高而增强,EDTA二钠盐参加合成的样品,由于在表面残留有机基团使发光强度降低。纳米粒子的猝灭浓度约为8%(摩尔分数,下同)。

反相高效液相色谱表征无定型聚芳醚酮（砜）成环解聚产物

建立了一种反相高效液相色谱表征无定型聚芳醚酮（砜）成环解聚产物的新方法.采用岛津VP-ODS C18反相色谱柱（150 mm×4.6 mm; 5 μm, i.d.）,以四氢呋喃/水为流动相,流速1.0 mL/min, 梯度淋洗方式;254 nm紫外检测,由此方法可将全部同系物组分有效地分离并可准确给出产物中各环状低聚体组分的百分含量.分析结果表明,酚酞聚醚酮、酚酞聚醚砜、双酚A聚砜经成环解聚反应高产率得到环状聚合体,最高成环率达97.57%.通过与激光质谱的比较证实了HPLC方法更适合于对成环解聚产物体系的表征.

Atomic force microscope investigation of large-circle DNA molecules

A circular bacterial artificial chromosome of 148.9 kbp on human chromosome 3 has been extended and fixed on bare mica substrates using a developed fluid capillary flow method in evaporating liquid drops. Extended circular DNA molecules were imaged with an atomic force microscope (AFM) under ambient conditions. The measured total lengths of the whole DNA molecules were in agreement with sequencing analysis data with an error range of +/-3.6%. This work is important groundwork for probing single nucleotide polymorphisms in the human genome, mapping genomic DNA, manipulating biomolecular nanotechnology, and studying the interaction of DNA-protein complexes investigated by AFM.

Ordered pattern formation from dewetting of polymer thin film with surface disturbance by capillary force lithography

The dewetting process of thin polystyrene (PS) film with built-in ordered disturbance by capillary force lithography (CFL) has. been investigated in situ by AFM. Two different phenomena are observed depending on the excess surface energy (DeltaF(gamma)) of the system. When DeltaF(gamma) is less than a certain critical value (i.e., the disturbance amplitude is under a critical value), the PS film would be flattened and become stable finally by heating above T-g. While, if the size of the disturbance amplitude is larger than the critical value, ordered PS liquid droplets form by further dewetting. The pattern formation mechanisms and influencing factors have been discussed in detail.

Electropolymerization of azure B on a screen-printed carbon electrode and its application to the determination of NADH in a flow injection analysis system

The electrooxidation polymerization of azure B on screen-printed carbon electrodes in neutral phosphate buffer was studied. The poly(azure B) modified electrodes exhibited excellent electrocatalysis and stability for dihydronicotinamide adenine dinucleotide (NADH) oxidation in phosphate buffer (pH 6.9), with an overpotential of more than 400 mV lower than that at the bare electrodes. Different techniques, including cyclic voltammetry, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy have been employed to characterize the poly (azure B) film. Furthermore, the modified screen-printed carbon electrodes were found to be promising as an amperometric detector for the flow injection analysis (FIA) of NADH, typically with a dynamic range of 0.5 muM to 100 muM.