Identification and determination of active components in Angelica dahurica Benth and its medicinal preparation by capillary electrophoresis

A micellar electrokinetic capillary chromatography (MECC) method for the separation of three active components, imperatorin (IM), isoimperatorin (IO) and scopoletin (SC), in Angelica dahurica Benth and its preparation was developed. The optimum separation for these analytes was achieved using 10 mM borate, 20 mM SDS and 10%(v/v) acetonitrile, with applied voltage of 22 kV. All experiments were performed using a 50.0 cm (42.5 cm effective length)x75 mum I.D. fused-silica capillary. The linear calibration range was 12.0-800.0 mug ml(-1) for IM, 10.0-850.0 mug ml(-1) for IO and 3.5-600.0 mug ml(-1) for SC. The recoveries of three constituents were from 91.3 to 108.7%. Also, the dissociation constant (pKa) of SC was determined by the CE method established in this paper.     

Studies on chemistry and immuno‐ modulating mechanism of a glycoconjugate from Lycium barbarum L.

The detailed structure of an O‐glycan derived from the fruit of Lycium barbarum L. was elucidated based on glycosidic linkage analysis, complete and partial acid hydrolysis, ¹H‐NMR and ¹³C NMR spectroscopy. According to the experiments, the carbohydrate was in the form of polysacchride (arabinogalactan) chains with highly branched 3, 4‐galactans and terminal arabinofuranosyl substituents. The immuno‐modulating mechanism of glycoconjugate and its glycan were investigated using tritium thymidine incorporation assay, flow cytometry assay and electrophoretical mobility shift assay (EMSA). The results suggested that the immunoactive components of the fruit of Lycium barbarum L. could enhance the splenocyte proliferation in normal mice and the effects of glycan chain were stronger than those of glycoconjugate. The target cell was most likely to be B‐lymphocyte, on which existed receptor binding site acting with the glycan. In addition, the immuno‐stimulatory effect of glycoconjugate (LbGp4) and its glycan (LbGp4‐OL) was associated with activating the expression of nuclear factor KB (NF‐KB) and activator protein 1 (AP‐1).     

Dichloro(2,2′‐diamino‐4,4′‐bi‐1,3‐thiazole‐N3,N3′)copper(II)

The title complex, [CuCl₂(C₆H₆N₄S₂)], has a flattened tetrahedral coordination. The Cu^II atom is located on a twofold rotation axis and is coordinated by two N atoms from a chelating 2,2′‐di­amino‐4,4′‐bi‐1,3‐thia­zole ligand and by two Cl atoms. Intramolecular hydrogen bonding exists between the amino groups of the 2,2′‐di­amino‐4,4′‐bi‐1,3‐thia­zole ligand and the Cl atoms. The intermolecular separation of 3.425 (1) Å between parallel bi­thia­zole rings suggests there is a π–π interaction between them.     

Preparation and adsorption performance of 5-azacytosine-functionalized hydrothermal carbon for selective solid-phase extraction of uranium

A new solid-phase extraction adsorbent was prepared by employing a two-step "grafting from" approach to anchor a multidentate N-donor ligand, 5-azacytosine onto hydrothermal carbon (HTC) microspheres for highly selective separation of U(VI) from multi-ion system. Fourier-transform infrared and X-ray photoelectron spectroscopies were used to analyze the chemical structure and properties of resultant HTC-based materials. The adsorption behavior of U(VI) onto the adsorbent was investigated as functions of pH, contact time, ionic strength, temperature, and initial U(VI) concentration using batch adsorption experiments. The U(VI) adsorption was of pH dependent. The adsorption achieved equilibrium within 30min and followed a pseudo-second-order equation. The adsorption amount of U(VI) increased with raising the temperature from 283.15 to 333.15K. Remarkably, high ionic strength up to 5.0molL(-1) NaNO(3) had only slight effect on the adsorption. The maximum U(VI) adsorption capacity reached 408.36mgg(-1) at 333.15K and pH 4.5. Results from batch experiments in a simulated nuclear industrial effluent, containing 13 co-existing cations including uranyl ion, showed a high adsorption capacity and selectivity of the adsorbent for uranium (0.63mmolUg(-1), accounting for about 67% of the total adsorption amount).     

Rapid Sample Pretreatment,Identification and Determination of Active Constitutents in Water‐soluble Radix isatidis Extract via MAE,ESI‐MS and RODWs‐HPLC

In this study, we successfully studied water‐soluble extract from Radix isatidis. Optimized conditions of MAE were listed, the sample can be extracted completely in 10 minutes under microwave power of 400W and solid/liquid ratio of 1:80. Active compounds in water‐soluble extract from R. isatidis were identified with HPLC‐DAD/ESI‐MS, these compounds followed by cytidine, uridine, guanosine, (R,S)‐goitrin and adenosine. RODWs–HPLC as a new sensitive chromatography were also first proposed and investigated, we favoringly used this method for simultaneous determination of these active constitutents in water‐soluble R. isatidis extract. Chromatographic separation was performed on a Diamonsil C18 column (5 μm, 150 mm × 4.6 mm) with a mobile phase gradient consisting of methanol and water at a flow‐rate of 1.0 mL/min, detection wavelengths 240, 250, 260 and 270 nm, the retention times of the tested five compounds were about 4.2, 5.8, 11.1, 14.2 and 20.8 min respectively, the limits of detection were 15, 12, 20, 5.8 and 24 ng/mL for cytidine, uridine, guanosine, (R,S)‐goitrin and adenosine respectively, their linear ranges were between 0.045 and 350 μg/mL with correlation coefficient (R) of 0.9998‐0.9999. The relative standard deviations (RSDs) of intra‐day and inter‐day assays were 0.30‐2.36% and 0.86‐2.54% respectively. Extraction recoveries were 94.25‐106.21%. This novel analytical method was shown to be simple, low‐cost, sensitive and reliable for multiple components in complex or undeveloped materials via MAE, ESI‐MS and RODWs‐HPLC.     

Janus 粒子在环境检测领域中的应用

Janus 粒子,也称为阴阳结构粒子或两面性非对称粒子,是指表面上具有两种或两种以上不同化学组成或性质的不对称粒子。目前,Janus 粒子因其独特的结构和功能已经逐渐成为生物医药、催化、材料以及防污等领域中的新型功能材料。在环境检测领域,Janus材料亦因其特殊的光学、磁学及电学性能,为提高检测灵敏度、选择性和稳定性等提供了新的研究方向。基于此,本文主要讨论了Janus材料在环境检测方面的特点、优势和相关应用。最后,本文基于本课题组的研究经验以及工作中所面临的问题,对本领域的发展和未来的研究方向提出了展望,以期对本领域的未来发展提供指导。     

Sulphur-Bridged BAl5S5+ with 17 Counting Electrons: A Regular Planar Pentacoordinate Boron System

At present, most of the reported planar pentacoordinate clusters are similar to the isoelectronic substitution of CAl₅⁺, with 18 counting electrons. Meanwhile, the regular planar pentacoordinate boron systems are rarely reported. Hereby, a sulphur-bridged BAl₅S₅⁺ system with a five-pointed star configuration and 17 counting electrons is identified at the global energy minimum through the particle-swarm optimization method, based on the previous recognition on bridged sulphur as the peripheral tactics to the stable planar tetracoordinate carbon and boron. Its outstanding stability has been demonstrated by thermodynamic analysis at 900 K, electronic properties and chemical bonding analysis. This study provides adequately theoretical basis and referable data for its experimental capture and testing.     

Facile electrochemical synthesis of a conducting copolymer from 5-aminoindole and EDOT and its use as Pt catalyst support for formic acid electrooxidation

5-Aminoindole and 3,4-ethylenedioxythiophene (EDOT) were copolymerized electrochemically on a carbon cloth (CC) electrode in an aqueous sulfuric acid solution. The as-prepared copolymer was characterized by cyclic voltammogram, SEM, and UV-vis and FT-IR spectra through which the electrochemical properties, structure, and composition of the as-obtained copolymer were determined. The electrochemical activity and stability of the as-formed copolymer are significantly improved in comparison with poly(5-aminoindole) due to the incorporation of EDOT units into the conjugated chain. The copolymer film-modified CC electrode was used as substrate for Pt particle deposition (denoted as Pt/copolymer/CC), and then, its catalytic activity towards formic acid electrooxidation was studied. Experimental results indicate that the catalytic activity of Pt/copolymer/CC towards formic acid electrooxidation is enhanced in comparison with that of Pt/homopolymer/CC, which can be attributed to the homogeneous distribution of Pt nanoparticles on the copolymer/CC substrate and the improved electrochemical activity of the copolymer film.     

PNA for one-base differentiating protection of DNA from nuclease and its use for SNPs detection

By the combination of peptide nucleic acid (PNA) with single-stranded DNA specific nucleases, alteration of a single base to another in DNA has been detected with high accuracy. Only the DNAs in DNA/PNA duplexes involving a mismatch are efficiently hydrolyzed by these enzymes, whereas fully matching sequences are kept intact. This difference is visually scored by adding 3,3'-diethylthiadicarbocyanine, which changes its color from blue to purple upon binding to DNA/PNA duplexes. These findings are applied to the convenient and straightforward detection of single nucleotide polymorphisms (SNPs). When the target site in the sample DNA is completely complementary with the PNA, a notable amount of DNA/PNA duplex remains and thus the solution exhibits purple color. In the presence of even one mismatch between PNA and DNA, however, the DNA is completely digested by the enzyme and therefore the dye shows its intrinsic blue color. The SNPs in the apolipoprotein E gene of human DNA have been successfully genotyped by this method.