Two new NiII and ZnII metal-organic frameworks of glutarate and 1,4-bis[(2-methyl-1H-imidazol-1-yl)methyl]benzene ligands: syntheses, structures and luminescence sensing properties.

Two new metal-organic frameworks (MOFs), namely, three-dimensional poly[diaquabis{µ2-1,4-bis[(2-methyl-1H-imidazol-1-yl)methyl]benzene}bis(µ2-glutarato)dinickel(II)] monohydrate], {[Ni2(C5H6O4)2(C16H18N4)2(H2O)2]·H2O}n or {[Ni2(Glu)2(1,4-mbix)2(H2O)2]·H2O}n, (I), and two-dimensional poly[[{µ2-1,4-bis[(2-methyl-1H-imidazol-1-yl)methyl]benzene}(µ2-glutarato)zinc(II)] tetrahydrate], {[Zn(C5H6O4)(C16H18N4)]·4H2O}n or {[Zn(Glu)(1,4-mbix)]·4H2O}n (II), have been synthesized hydrothermally using glutarate (Glu2-) mixed with 1,4-bis[(2-methyl-1H-imidazol-1-yl)methyl]benzene (1,4-mbix), and characterized by single-crystal X-ray diffraction, IR and UV-Vis spectroscopy, powder X-ray diffraction, and thermogravimetric and photoluminescence analyses. NiII MOF (I) shows a 4-connected 3D framework with point symbol 66, but is not a typical dia network. ZnII MOF (II) displays a two-dimensional 44-sql network with one-dimensional water chains penetrating the grids along the c direction. The solid-state photoluminescence analysis of (II) was performed at room temperature and the MOF exhibits highly selective sensing toward Fe3+ and Cr2O72- ions in aqueous solution.

Application of high-speed counter-current chromatography combined with macroporous resin for rapid enrichment and separation of three anthraquinone glycosides and one stilbene glycoside from Rheum tanguticum.

In this paper, an efficient method was successfully established by the combination of macroporous resin (MR) and high-speed counter-current chromatography (HSCCC) for rapid enrichment and separation of aloe-emodin 8-O-ß-D-glucoside, emodin 1-O-ß-D-glucoside, emodin 8-O-ß-D-glucoside and piceatannol 4'-O-ß-D-(6″-O-gallate)-glucoside. Six kinds of macroporous resins were investigated in the first step and X-5 macroporous resin was selected for the enrichment of the target compounds. The recoveries of the target compounds reached 89.0, 85.9, 82.3 and 84.9% respectively after 40% ethanol elution. In the second step, the target compounds were separated by HSCCC with a two-phase solvent system composed of chloroform/ethyl acetate/methanol/water (8:1:6:5, v/v). The established method will be helpful for further characterization and utilization of Rheum tanguticum. The results demonstrate that MR coupled with HSCCC is a powerful technique for separation of bioactive compounds from natural products.

A sensitive and selective HPLC-FLD method with fluorescent labeling for simultaneous detection of bile acid and free fatty acid in human serum.

A sensitive and selective method using 2-(7H-dibenzo[a,g]carbazol-7-yl)ethyl 4-methylbenzenesulfonate (DBCETS) as a new fluorescent labeling reagent has been proposed for simultaneously detecting BA and FFA by HPLC with fluorescence detector. The developed method offered the low detection limits of 0.42-0.70 and 0.28-0.57 ng/mL for BA and FFA, respectively. Compared with the reported methods, the proposed method here is capable of offering higher detection sensitivity and selectivity, with less cost and lower volume of sample preparation. This method was validated to ensure high accuracy and precision, and the reliability of its results. When applied to the serum samples of healthy volunteers and patients with hepatic carcinoma, it showed excellent applicability.

Amphiphilic block copolymer-stabilized PtRu nanoparticles highly dispersed on multi-walled carbon nanotube for methanol oxidation.

We report a one-pot synthesis of amphiphilic block copolymer-stabilized PtRu nanoparticle modified multi-walled carbon nanotubes (MWCNTs) using RuCl(3)·xH(2)O and H(2)PtCl(6)·6H(2)O as ruthenium and platinum sources, and block copolymer poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) as stabilizer agent. PtRu alloyed nanoparticles with an average diameter of 4.6nm are well decorated homogeneously on the exterior surfaces of the MWCNTs. The electrochemical catalytic activity for methanol oxidation of PtRu/MWCNTs and commercial PtRu/C (E-TEK) is comparatively investigated using cyclic voltammetry and chronoamperometry. It is revealed that the PtRu nanoparticle modified MWCNT samples display an enhanced electrochemical catalytic activity than commercial PtRu/C electrode. These results show that PtRu nanoparticles may find applications to fuel cells.

Development of a new HPLC method with precolumn fluorescent derivatization for rapid, selective and sensitive detection of triterpenic acids in fruits.

Triterpenic acids are widespread in plants and have multiplicity of biological properties. Unfortunately the method for accurate analysis of these compounds remains poorly investigated. This study proposed a highly sensitive and selective precolumn derivatization method for accurate determination of five triterpenic acids (betulinic acid, betulonic acid, maslinic acid, ursolic acid and oleanolic acid) in fruits using acridone-9-ethyl-p-toluenesulfonate (AETS) as fluorescent labeling reagent by HPLC with fluorescence detection (FLD). Response surface methodology was employed to optimize the derivatization reaction, ensuring the sufficient labeling of the analyzed components. The rapid separation of five triterpenic acids could be achieved in as little as 16 min. This developed method offered the exciting detection limits of 1.68-2.04 ng/mL. When applied to several popular fruits in China, it revealed satisfactory applicability and reproducibility. This developed method also exhibits powerful potential for accurate detection of triterpenic acids from other foodstuffs and nature products.

[Determination of trace elements in Niuhuang Jiedu tablets by microwave digestion and ICP-AES].

Niuhuang Jiedu tablets were digested with HNO3-H2O2 system by microwave digestion. The fourteen trace elements of As, Ca, Mg, Al, Mn, Sr, Ba, Se, Ni, Cd, Cu, Zn, Mo and Pb in the solution were determined by ICP-AES. The ICP-AES result proved to be reliable by adding standard recovery experiment to the process. By comparison with the result of chemical experiment, thr present method was accurate, quickly-accessible, and convenient. It was used for Niuhuang Jiedu tablets with result satisfactory.