固定化单宁对酒类营养成分的吸附性能研究

采用固定化单宁对酒中可能存在的营养成分蛋白质、氨基酸、糖类、有机酸、乙醇和铁离子等进行吸咐试验。结果表明：固定化单宁对不同营养成分的吸附率差别明显，它通过氢键和疏水作用对蛋白质有较大的吸附率，通过多个酚羟基与中心铁离子形成螯合物而对其有较大的吸附率，对氨基酸、糖、有机酸和乙醇等营养成分或风味物质吸附率不大，固定化单宁可以作为一种较为理想的酒类处理剂。     

Structural characterization of nanopatterned surfaces

In this work, chemically and topographically nanopatterned surfaces were produced by a top-down processing approach for biosensing devices. The nanopatterning was the result of the combination of plasma polymerisation (pp) of biofunctional materials and colloidal lithography techniques. The morphological and chemical properties induced by the plasma deposition-etching treatment were characterised by optical method combining ellipsometry and Fourier Transform Infrared spectroscopy studies. This method supported by atomic force microscopy measurements, allowed the full optical characterization of each step of the top-down process. The optical characterization of the end-up nanopatterned samples demonstrated that the chosen process is able to produce well-defined nanostructured surfaces with controlled chemical and morphological properties.     

In vitro screening of the action of non-steroidal anti-inflammatory drugs on hypochlorous acid-induced hyaluronan degradation

The antioxidative effect of two non-steroidal anti-inflammatory drugs was studied in vitro by measuring the kinetics of degradation of high-molecular weight hyaluronan (HA) in a system comprising hypochlorous acid + CuCl₂ + ascorbic acid using a Brookfield rotational viscometer equipped with a Teflon cup and spindle of coaxial cylindrical geometry. The changes in HA chemical structure were investigated by chemiluminometry. When sodium naproxen was added to the system during a running degradative process its inhibitory effect was clearly shown. The inhibition was dependent on the drug concentration. However, when this drug was added to the system before the initiation of HA degradation, no inhibition was seen even at the highest drug concentration tested. The inhibitory effect of acetylsalicylic acid was achieved with a relatively low concentration of the drug and was independent of the experimental model used.     

Synthesis of aromatic poly(thioether ketone)

Aromatic poly(thioether ketone)s were prepared by the direct polycondensation of aromatic dicarboxylic acids with aryl compounds containing ether or sulfide structures using phosphorus pentoxide/methanesulfonic acid (PPMA) as a condensing agent and solvent. Polycondensation proceeded smoothly and produced aromatic poly(thioether ketone)s with inherent viscosities up to 0.73 dL/g. The synthesis of substituted aryl ketones by the reaction of substituted benzoic acids with aryl compounds in PMMA was studied in detail to demonstrate the feasibility of the reaction for polymer formation. The thermogravimetry of the aromatic poly(thioether ketone)s showed a 10% weight loss in air and nitrogen at around 450 and 460°C, respectively. © 1992 John Wiley & Sons, Inc.     

Influence of humic substances on sorption and methylation processes of inorganic- and organo-tin species

The influence of humic substances on sorption and methylation processes for inorganic- and organotin species is presented. Four sediment samples from different locations of the Rivers Elbe, Mulde and Spittelwasser, Germany, with different organotin and humic contents were selected to extract the humic and fulvic acids. The various fractions—the original sediment, the humic acid, the fulvic acid and the residual sediment—were analysed for their organotin content. The individual buyltin species show quite different distribution patterns. Monobutyltin is found mostly associated with humic acids. Dibutyltin shows a nonunique behaviour. At low total organotin content, dibutyltin is found bonded to humic and fulvic acids, whereas at high organotin content dibutyltin is distributed more with the residual sediment. Most of the tributyltin remains in the sediment unextracted; only small quantities of it are in the fulvic acid fraction. Tetrabutyltin is only in the humic acid fraction when it binds to humic matter; it mostly remains in the sediment. General observations indicate that ionic butyltin species bind to fulvic acids whereas the non-polar tetrabutyltin is not found in the fulvic acid fractions in any of the samples. The appearance of monomethyl- and dimethyl-tin species in the humic and fulvic acid fractions after the alkaline extraction was surprising. There is a correlation between the humic content of the sample and the formation of methyltin species. Evidence is provided by experiments that humic substances act as methylation agents.     

Response to high acidity and basicity at a platinum electrode in chronopotentiometry

A simple and rapid method is developed to determine the high acidity and the basicity of solutions by chronopotentiometry with a platinum working electrode. The acidity range from 5.0 mol/l H⁺ to 1.0 mol/l OH⁻ can be measured by the adjustment of deposition potential and time. The response mechanism to acidity and basicity has been explored. The transition potential plateau in chronopotentiograms is caused from the oxidation of hydrogen adsorbed on electrode surface.     

原子吸收法在有机分析中的应用（Ⅵ）香烟中氢氰酸的分析

原子吸收法在有机分析中的应用（Ⅵ）香烟中氢氰酸的分析谢志海，郎惠云，高云（西北大学化学系，西安，７１００６９）关键词：氢氰酸，测定，原子吸收光谱香烟中的尼古丁，烟焦油等含氮有机物燃烧后将产生氢氰酸，吸入人体后极为有害。国外在这方面的研究始于七十年代，...     

Influence of boric acid on the electrochemical deposition of Ni

The electrolytic deposition of Ni onto a paraffin-impregnated graphite electrode from supporting chloride electrolyte (0.5 mol dm⁻³ NaCl) adjusted to the required pH using dilute HCl is investigated. The effect of electrolyte composition on the Ni electrodeposition is studied using linear sweep voltammetry in the cathodic region. An elimination voltammetry procedure was applied to evaluate the polarization curves. The aim of this work was to deduce the mechanism of Ni reduction in the chloride bath as well as the influence of boric acid on this. Positively-charged NiCl⁺ ions were found to be the electroactive particles in the Ni reduction mechanism. The strong competition between the NiCl⁺, Cl⁻ and H⁺ ions for active sites at the electrode is discussed. Kinetically-controlled adsorption/desorption processes of various species were also confirmed using elimination voltammetry with a linear scan. The evolution of gaseous hydrogen, catalyzed by the freshly-deposited Ni, accompanies the electrodeposition process. The presence of boric acid at a sufficiently high concentration inhibits the deposition of Ni and, at the same time, improves the morphology and brightness, as well as the adhesion of the deposited Ni. Elimination voltammetry with a linear scan is an efficient way to evaluate current–potential curves that reflect the electrodeposition of one-component Ni coatings. By eliminating selected currents, additional interesting and useful information can be obtained from voltammetric data.     

Synthesis and properties of poly(amic acid)s and polyimides based on 2,2′,6,6′‐biphenyltetracarboxylic dianhydride

Poly(amic acid)s (PAAs) having the high solution stability and transmittance at 365 nm for photosensitive polyimides have been developed. PAAs with a twisted conformation in the main chains were prepared from 2,2′,6,6′‐biphenyltetracarboxylic dianhydride (2,2′,6,6′‐BPDA) and aromatic diamines. Imidization of PAAs was achieved by chemical treatment using trifluoroacetic anhydride. Among them, the PAA derived from 2,2′,6,6′‐BPDA and 4,4′‐(1,3‐phenylenedioxy)dianiline was converted to the polyimide by thermal treatment. The heating at 300 °C under nitrogen did not complete thermal imidization of PAAs having glass‐transition temperatures (T_g)s higher than 300 °C to the corresponding PIs. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6385–6393, 2006