Behaviour of organic pollutants in paper and board samples intended to be in contact with food

This paper deals with the study of volatile compounds present in a set of three paper and board (P&B) samples of different composition, surface treatment, grammage and thickness. The volatile compounds released by the packaging material (P&B) can be trapped on the food and may then affect the safety and health of consumers. To evaluate if the recycled P&B could be used as food packaging material, adsorption studies have been performed with a selection of chemical substances. The adsorption isotherms are provided. Partition coefficients between paper and air have been calculated for a series of volatile compounds used as model compounds to represent different families of contaminants commonly present in P&B. Values from 4 to 3243 were obtained at different temperatures. The analysis of volatile compounds have been carried out by automatic headspace coupled on-line with GC/MS in SIM mode. The results obtained are shown and discussed.     

含磺酸,羧酸双功能基树脂对混合氨基酸的分离性能研究

对苯乙烯-丙烯腈-二乙烯基苯(S/AN/DVB)交联共聚机理研究曾发现,丙烯腈作为第三单体,可使DVB竞聚率比在S/DVB共聚体系中降低,相互分离显著,从而有利于合成性能较好的离子交换树脂;本文在此基础上,将S/AN/DVB共聚体中的氰基水解成羧基来合成含磺酸、羧酸双功能基树脂,解决了前人研究中仅有50％的氰基水解成羧基的问题,并首次将这种树脂应用于混合氨基酸的分离。     

The Surface Imprinted Polystyrene Beads Prepared via Emulsion Templates

In this paper, the surface imprinted cross-linked polystyrene beads were prepared via suspension polymerization with styrene (St), divinylbezene (DVB), polyvinyl alcohol (PVA1788),the mixture of Span 85 and xylene or the mixture of Span 85 and paraffin as monomer,cross-linking agent, dispersion stabilizer and templates, respectively. The results indicate that there are dense cavities on the surface of beads, and the diameter and density of cavity are related with the composition and amount of emulsion template. The forming mechanism of cavity from thermodynamics and dynamics was proposed.     

The oxygen reduction reaction at silver electrodes in high chloride media and the implications for silver nanoparticle toxicity

The oxygen reduction reaction (ORR) at neutral pH in various aqueous chloride-containing solutions was investigated voltammetrically. In particular, the ORR was performed in high chloride containing aqueous media including authentic and synthetic seawater under oxygen saturated conditions and compared with that in aqueous nitrate and perchlorate media. The experimental voltammograms revealed a two-electron process forming hydrogen peroxide in low chloride media. In contrast, high concentration chloride solutions, including both synthetic and authentic seawater showed an increase of overpotential, accompanied by a splitting of the voltammetric peak into two one-electron features indicating the formation of superoxide in the first step and its release from the silver-solution interface. The implications for silver nanoparticle toxicology are discussed given the markedly greater toxicity of superoxide over peroxide and the high levels of chloride in biological media as well as in seawater.

Superoxide produced at silver electrode in seawater.     

二(2,4,4-三甲基戊基)膦酸萃取分离稀土元素(Ⅲ)的研究

本文研究了二(2,4,4-三甲基戊基)磷酸(Cyanex 272)的煤油溶液在不同介质(HCI,HNO_3)中对三价混合稀土的萃取分离性能.观测了平衡水相酸度对萃取平衡的影响,由酸度曲线求出相邻元素的平均分离系数,并考察了酸度对反萃取平衡的影响.比较了HCI和HNO_3介质中,Cyanex 272对混合稀土(Ⅲ)的萃取性能.     

四硫富瓦烯为介体的碳纤维束葡萄糖氧化酶微电极的研究

本文研究了一种将电子介体四硫富瓦烯(TTF,Tetrathiafulalene)引入葡萄糖氧化酶微电极的新方法,制成了TTF为介体的碳纤维束葡萄糖氧化酶微电极。该电极制作简单,响应迅速、灵敏,电极寿命可达15天。葡萄糖浓度在1。0×10~(-4)～1.5×10~(-3)mol/L范围内有线性关系。检出限为7×10~(-5)mol/L。用于人体血样中葡萄糖测定获得满意结果。     

两个具有PTP1B抑制活性的4-羟基丁内酯化合物的全合成研究

Two new naturally 4-hydroxylated butenolides were concisely synthesized in excellent enantiomeric purities. An aldol condensation and a Suzuki reaction served successfully as the key steps in the synthesis.     

生物质裂解产物的制备及HPLC检测其成分的虚拟仿真实验开发

In order to improve university laboratory teaching and practical education under the background of information technology, as well as overcome the difficulty for practical training, develop a virtual simulation experiment platform for rapid pyrolysis of natal materials and high-performance liquid chromatographic (HPLC) detection of its components. The experiment integrates the actual operation process of the plant to produce cleaved products by rapid pyrolysis of biomass with HPLC detection. The virtual experiment is divided into biomass sample pretreatment, rapid biomass pyrolysis, bio-oil extraction, and HPLC determination of complex components, making the biomass cleavage workshop "real" through simulation. This virtual simulation experiment fully integrates the utilization of biomass resources and basic chemistry courses (such as organic chemistry, instrumental analysis, chemical engineering principles, etc.), which are widely involved in agricultural and forestry majors with advantageous characteristics value.     

CO(υ)高振动激发态向C2H2的振动传能研究

用时间分辨富里叶红外发射谱研究了高振动激发态ＣＯ向Ｃ２Ｈ２的传能，得到了ＣＯ（ｖ＝１－３）各振动态布居及其随时间的变化。利用微分法解出弛豫微分方程组，获得ＣＯ（ｖ＝１－３）向Ｃ２Ｈ２的传能速率常数分别为：２．０±０．１，６．０±０．２和９．４±０．８（１０＾－１３ｃｍ＾３·ｍｏｌｅｃｕｌｅ＾－１·ｓ＾－１）。传能速率随着振动量子数的增加而迅速增加。ＣＯ的振动能应向Ｃ２Ｈ２的对称伸缩模ｖ２近共振Ｖ－     

氟硅烷自组装单分子膜的制备及其摩擦学性能

利用分子自组装技术制备了全氟辛酰胺丙基硅烷单分子膜,用X射线光电子能谱(XPS)对组装膜的表面元素进行了表征;接触角测试表明,该组装膜具有很好的疏水-疏油性,其对水的接触角高达105°,对正十六烷的接触角为50°.摩擦磨损实验结果表明,全氟辛酰胺丙基硅烷自组装单分子膜可以大大降低基片的摩擦系数,使载玻片的摩擦系数从0.85左右降低到0.14左右,而且低负荷下具有很好的耐磨性.