U-PLS/RBL三维荧光法测定藤络宁胶囊中东莨菪内酯含量

研究了东莨菪内酯的荧光性质和最佳实验条件,发现体系的最佳p H值为9.0,最大激发波长为375nm,最大发射波长为460 nm。在激发波长310~420 nm,发射波长400~550 nm范围内采集实际样本的三维荧光数据矩阵。采用二阶校正中的U-PLS/RBL(Unfolded partial least squares coupled to residual bilinearization)解析三维荧光数据阵,成功地测定了藤络宁胶囊中的东莨菪内酯含量。用U-PLS/RBL解析藤络宁胶囊中的东莨菪内酯含量,结果与HPLC方法一致,说明荧光解析法结果准确可靠。用U-PLS/RBL解析藤络宁胶囊样品的加标回收率为100.4%。相比于色谱方法,荧光方法具有操作费用低及绿色环保等优点。     

The activity and stability of PdCl<Subscript>2</Subscript>/C-N catalyst for acetylene hydrochlorination

Carbon supported PdCl₂ is highly active in catalyzing acetylene hydrochlorination reaction, but deactivates rather quickly. Upon nitrogen doping in the carbon structure, the stability of the PdCl₂ catalysts is significantly improved. Furthermore, the results show that 900 °C is a preferred doping temperature. The acetylene conversion keeps above 90% even after 1200 min time on stream whereas the one without nitrogen doping drops to below 10% after 450 min. The stabilizing mechanism of nitrogen doping on catalyst was studied.     

Construction of Supramolecular Assemblies from Self‐Organization of Amphiphilic Molecular Isomers

Amphiphilic coil‐rod‐coil molecules, incorporating flexible and rigid blocks, have a strong affinity to self‐organize into various supramolecular aggregates in bulk and in aqueous solutions. In this paper, we report the self‐assembling behavior of amphiphilic coil‐rod‐coil molecular isomers. These molecules consist of biphenyl and phenyl units connected by ether bonds as the rod segment, and poly(ethylene oxide) (PEO) with a degree of polymerization of 7 and 12 as the flexible chains. Their aggregation behavior was investigated by differential scanning calorimetry, thermal optical polarized microscopy, small‐angle X‐ray scattering spectroscopy, and transmission electron microscopy. The results imply that the molecular structure of the rod building block and the length of the PEO chains dramatically influence the creation of supramolecular aggregates in bulk and in aqueous solutions. In the bulk state, these molecules self‐organize into a hexagonal perforated lamellar and an oblique columnar structure, respectively, depending on the sequence of the rod building block. In aqueous solution, the molecule with a linear rod segment self‐assembles into sheet‐like nanoribbons. In contrast, its isomer, with a rod building block substituted at the meta‐position of the aryl group, self‐organizes into nanofibers. This is achieved through the control of the non‐covalent interactions of the rod building blocks.     

A glassy carbon electrode modified with carbon nano-fragments and bismuth oxide for electrochemical analysis of trace catechol in the presence of high concentrations of hydroquinone

Microchimica Acta - A glassy carbon electrode was modified with carbon nanofragments and bismuth oxide, and the resulting electrode (CNF-Bi/GCE) was applied to the voltammetric determination of...     

Surface-enhanced Raman scattering from surfactant-free 3D gold nanowire networks substrates

A useful method for the fabrication of three-dimensional gold nanowire networks based on the chemical reduction of HAuCl4 with trisodium citrate was presented. The coverage of the 3D gold nanowire networks was tunable by altering precursor concentration. The as-prepared 3D gold nanowire networks could be used as surface-enhanced Raman scattering (SERS) substrates and examined by 4-aminothiophenol (4-ATP) as a probe molecules. Since the proposed strategy is simple, cost-effective and reproducible for the mass production of network-like gold films irrespective of the kinds of the underlying substrates, it is expected to play an important role in the development of surface plasmon-based analytical devices.     

Studies on the Electrochemical Properties of Amphiphilic Ferrocenylimines Compounds

A series of amphiphilic ferrocenylimine compounds (four amphiphilic ferrocenylimines and four corresponding palladium complexes) were synthesized and their electrochemical characters were also investigated in detail. The results revealed that the redox of ferrocene derivatives was assumed by the ferrocene group and affected by substituent groups. Some effect rules were discovered and are described here. Moreover, the dynamics parameters of the electrode process were detected by several electrochemistry techniques.     

Simultaneous determination of 24 sulfonamide residues in meat by ultra-performance liquid chromatography tandem mass spectrometry

The present study used the liquid extraction pretreatment method and developed an ultra-performance liquid chromatography triple quadrupole tandem mass spectrometry (UPLC-MS/MS) for the simultaneous determination of 24 kinds of sulfonamide residues in meat. The meat samples were homogenized, extracted and deproteinized by acetonitrile, defatted by n-hexane, and further liquid-liquid extracted by ethyl acetate. All of 24 sulfonamide residues were simultaneously separated and determined by UPLC-MS/MS within 15 min. The sulfonamide residues were monitored via the ESI(+) ionization method and quantified by six-channel multiple reaction monitoring (MRM). The calibrations were performed in sample matrixes by the isotope dilution method and the interference effect of sample matrixes on the ionization was effectively eliminated. Good linear relationship (R(2)=0.991-0.999) was observed within the concentration range of 0.2-50 microg/kg. Satisfied recoveries (67.8-113.9%) of all the sulfonamides were demonstrated in different standard-spiked levels except sulfanitran (SNT). The analytical category, separation speed, selectivity, sensitivity and repeatability of sulfonamides using UPLC-MS/MS were significantly improved compared to other analytical methods. Quantitative results of 240 meat samples demonstrated that the present method has a convenient operation and good practicability, which can be applied to the quantitative analysis of a large number of samples.     

Variability of SO2 in an intensive fog in North China Plain:Evidence of high solubility of SO2

A field experiment was conducted in an intensive fog event between November 5 and November 8,2009, in a heavily SO₂-polluted area in North China Plain（NCP）,to measure SO₂ and other air pollutants,liquid water content（LWC） of fog droplets,and other basic meteorological parameters.During the fog period, the concentrations of SO₂ showed large variability,which was closely related to the LWC in the fog droplets.The averaged concentration of SO₂ during non-fog periods was about 25 ppbv,while during the fog period,it rapidly reduced to about 4-7 ppbv.Such large reduction of SO₂ suggested that a majority of SO₂（about 70%-80%） had reverted from gas to aqueous phase on account of the high solubility of SO₂ in water in the fog droplets.However,the calculated gas to aqueous phase conversion was largely underestimated by merely using the Henry’s Law constant of SO₂,thus suggesting that aqueous reaction of SO₂ in fog droplets might play some important role in enhancing the solubility of SO₂.To simplify the phenomenon,an "effective solubility coefficient" is proposed in this study.This variability of SO₂ measurement during the extensive fog event provides direct evidence of oxidation of SO₂ in fog droplets, thus providing important implications for better understanding of the acidity in clouds,precipitation,and fogs in NCP,now a central environmental focus in China due to its rapid economic development.