[Comparative investigation of molecules releasing from intra-hollow calcium-alginate capsules using fluorimetry].

In this paper, the authors employ three different types of dye molecules, Nile red, Rhodamine 6G, fluorescein and a fluorescent protein-R-phycoerythrin (R-PE). The Rhodamine 6G is positively charged molecules, fluorescein is negatively charged molecules, and Nile red is neutral molecules. The R-phycoerythrins have either a net positive or negative charge which is balanced at the isoelectric point (4.22). It is negatively charged molecules also under our experimental condition. The Nile red, rhodamine 6G, fluorescein and R-phycoerythrin are trapped into alginate calcium hollow capsule respectively. The diffusion processes of those molecules from calcium alginate capsule to solution are measured based on a fluorescence method. The results indicate that electrical characteristics of encapsulated molecules have effect on their diffusion behaviors. The positively charged rhodamine 6G is well accordance with a model of control release from porous polymer membranes. The neutral molecules not only can be released from porous polymer framework, they also can directly dissolve out through polymer membrane. The electrostatic repulsion between fluorescein and negatively charged calcium alginate membranes will accelerate the molecular motion, which is propitious to molecules directly dissolving out through polymer membrane. Based on Fick's law of diffusion, R-PEs can be releases from porous polymer framework It shows the longest equilibrium time. Comparing neutral molecules, negatively and positively charge molecules show the stronger interaction on electric polymer membrane, which results in that the diffusion coefficients of rhodamine 6G and fluorescein are less than that of neutral molecule Nile red. The consequences obtained here should readily explain analogous control releasing behaviors of other functional molecules.

[A study of non-spectral interference of iron matrix and its mechanisms in ICP-AES analysis].

In the present paper non-spectral Interference of iron matrix whose concentration ranges from 0 to 5 mg x mL(-1) has been studied by using ICP-AES. And its mechanisms are discussed through calculating every terms of the interference function and investigating the relation between the values of them and Fe matrix concentration. The results show that in a certain concentration range (0-5 mg x mL(-1)) Fe matrix has no significant influence upon excitation temperature and electronic number density. Most of the elements' activity coefficient terms decreases with the increase of Fe matrix concentration. And the contribution of each term to the interference function is different according to atomic line and ionic line. It is the difference in ionization term between atomic line and ionic line that causes this.

[Antioxidant activity and spectroscopic behavior study with DNA of several Salen Mn(II), Eu(III) complexes].

Five kinds of Salen Mn(II) and two kinds of Eu(III) complexes were synthesized. Under the system of NBT/L-methionine, which creates and detects O2*-, the complexes of antioxidant activity were studied, and the conclusion revealed that all Mn(II) complexes have obvious antioxidant activity. The fluorescence study indicated that all the Salen metal complexes could bind with DNA, which shows their potential anticancer activity.

[An enzyme sensor for phenolic compounds analysis].

Phenolic analysis was established on the immobilized horseradish peroxidase (HRP) catalyzed oxidation reaction. It subsequently catalyzed oxidative coupling of phenol with 4-aminophenazone using aqueous hydrogen peroxide to form intensely colored products for spectrophotometric analysis. HRPs were trapped in sol-gel matrix in a mild procedure. The immobilized HRPs maintain almost identical enzymatic activity as those in solution. BET analysis indicates that the silica itself is a porous structure with the average pore diameter of 2.95 nm. It permits small size molecules i. e. hydrogen peroxide, phenol and 4-aminophenazone to diffuse into the matrix while large molecules like enzyme (HRP) remain in the pores. It thus allows a biocatalysis to occur and makes the most out of the enzymes encapsulated in the silica matrix to stand against leakage so that the immobilized horseradish peroxidase could be recycled. The method can be employed for 2-chlorophenol, 3-chlorophenol or 2,4-dichlorophenol analysis as well. The feasibility of recycle on immobilized enzyme is evaluated. Although enzymatic activities are obviously decreased after repeated utilization of 9 times, the method definitely offers a potential spectrophotometric biosensor for phenolic compounds analysis.

[Compositions and structure characterizations of coal tar refined soft pitch].

High temperature coal tar was used as raw materials, and was distilled to 280 degrees C for getting coal tar soft pitch. Then refined soft pitch was obtained by solvent extracting and subsequent settlement method. Its soft point was 32 degrees C; the group compositions consisted of 53.67% heptane soluble, 39.47% heptane insoluble but toluene soluble, 6.86% toluene insoluble and 0.06% quinoline insoluble. The relative average molecular weight was about 292. Its average molecular formula was C22.22 H16.32 N0.12 S0.06 O0.33; the total content of heteroatom was less than 1. IR analytic results showed that its heteroatom O existed in the R-O-R and Ar-O-R structure; its heteroatom N existed in the R-NH-R and -N=, with the latter being primary. Its average structure was obtained by improved Brown-Lander model: five-membered condensed rings. UV analysis indicated that the majority was linear arrangement, and the minority was surface arrangement; namely, the chemical structure of the samples was mainly the cata-condensed structure, while the minority was peri-condensation.

Multi-walled carbon nanotubes as a solid-phase extraction adsorbent for the determination of chlorophenols in environmental water samples.

Multi-walled carbon nanotubes (MWCNs) are used as adsorbent for solid-phase extraction (SPE) of several chlorophenols (CPs). CPs were adsorbed on MWCNs cartridge, then desorbed with pH 10.0 methanol, finally determined by HPLC. Under the optimized conditions, detection limits of 0.08-0.8 ng mL(-1) were obtained. The method had been applied to analyze the five CPs in tap water and river water.

[Study on enhancing effect of ethanol in lower power ICP].

The effects of ethanol on physical propesties (density, viscosity, surface tension) of sample solution, plasma temperature and electron number density in the ICP were investigated. Detection limits of varying elements in ethanol-water system were determined. The experimental results showed that the gas temperature, excitation temperature and electron number density were lower than those in water solution, the electron temperature and ionization temperature were slightly reduced, while the velocity of aerosol to the plasma increased. The lower detection limits of rare earth elements were observed. The detection limits of other elements were the same as those with water solution. The mechanism of the enhancing effect was discussed.