Pulse radiolysis of one-electron oxidation of rare tricyclic nucleoside derivative

~~Pulse radiolysis of one-electron oxidation of rare tricyclic nucleoside derivative@赵红卫$Shanghai Institute of Nuclear Research, Chinese Academy of Sciences! Shanghai 201800,China @江致勤$Department of Chemistry, Tongji Unviersity!Shanghai 200092,China @窦大营$Shanghai Institute of Nuclear Research, Chinese Academy of Sciences! Shanghai 201800,China @吴铁一$Shanghai Institute of Nuclear Research, Chinese Academy of Sciences! Shanghai 201800,China @王文锋$Shanghai…     

液相合成方形PbS纳米晶的光学特性

采用一种简单、温和的液相合成方法制备了PbS纳米晶，利用透射电镜和高分辨透射电镜对PbS纳米晶的形貌与晶型结构进行了表征．研究了PbS纳米晶的光学吸收和光致发光特性，并比较分析了包覆剂聚乙烯吡咯烷酮(PVP)和回流时间对产物光学特性的影响．结果表明：PVP分子链中的O原子与纳米晶表面吸附的游离态Pb原子形成Pb-O配位键，使产物的激子吸收大为减弱，同时引起了表面浅束缚态能量的升高，最终导致了荧光淬灭现象．     

痤疮患者血清中微量元素含量的变化

测定了52例痤疮患者血清Ca,Mg,Zn,Cu,Fe五种元素的含量。结果表明，痤疮患者血清Zn水平显著低于正常人（P＜0．001），血清Ca,Mg,Cu,Fe水平则与正常人无差别（P＞0．05）。部分病人口服补充锌剂后痤疮症状有所好转。提示痤疮患者应重视体内微量元素含量的变化，并做适当的补充。     

Simple and versatile operational fractionation of Fe and Zn in dietary products by solid phase extraction on ion exchange resins

A simple and versatile protocol, based on use of solid phase extraction on strong ion exchangers and off-line detection by flame atomic absorption spectrometry, was devised to fractionate iron and zinc in common dietary food and beverages products, i.e., bee honeys, fruit juices and tea infusions. In the procedure proposed, cation exchanger Dowex 50Wx4 and anion exchanger Dowex 1x4 were used separately for distinguishing broadly meant the cationic metal fraction and the fraction of stable anionic metal complexes, respectively, after retention of metal species and their exhaustive elution by means of a 4.0 mol l⁻¹ HCl solution. The third fraction, referred to the residual metal species, was retrieved by difference between total soluble metal contents and sum of metal quantities in separated cationic and anionic fractions. The fractionation pattern observed for both metals was described and discussed.     

Electrochemistry of metallofullerene films: the major isomer of Dy@C82

Solution-cast films of the major isomer of Dy@C(82) (Dy@C(82)(I)) have been studied by cyclic voltammetry (CV) in acetonitrile. The films are found to display pronounced and stable redox responses in solution. The reduction/reoxidation processes exhibit large splittings between the first two reduction and reoxidation waves. However, a pair of reversible oxidation and rereduction waves is observed after the reoxidation of a reduced film. The characteristics and the inter-relationship of these waves are uncovered by the CV technique, scanning electron microscopy (SEM), and UV/Vis-NIR spectra. A possible mechanism is proposed for the film electrode processes, which emphasizes the redox-induced structural reorganization of the metallofullerene film by the incorporation and expulsion of electrolyte ions into and out of the film. The influence of the counter ion diffusivity and the ion-pair stability on the electrochemical activity of the metallofullerene film has also been indicated.     

PAN共沉淀富集原子吸收测定饮水和人发中的微量锰

使用PAN-Ni(Ⅱ)共沉淀体系分离富集、微量流向进样火焰原子吸收光谱测定饮水和人发中的微量锰。样品中的共存元素不干扰测定，锰的标准加入回收率90%-108%之间。12次重复测定锰含量为0.15μg/mL的试样溶液的变异系数为4.6%,本法简便快捷,取得了较满意的结果.     

中药一枝黄花、黄连、天麻、蛇床子中8种微量元素的测定

采用原子吸收光谱仪对一枝黄花、黄连、天麻、蛇床子中Fe、Ca、Mg、Mn、Cr、Cu、Zn、Pb八种无机元素的含量进行了测定,为进一步研究其药理和用途提供基础。     

平台蒸发溴化铟分子吸收光谱法测定痕量溴的研究

本文对 InBr 分子吸收光谱法测定溴进行了研究。使用平台大大降低了 InO 背景吸收,使信-背比增大十倍。铟先于溴进样可提高 InBr 吸收信号。铬空心阴极灯可代替氘灯作为测定光源。方法灵敏度为8.5ng/0.0044吸收。     

Solid phase extraction of gold by sorption on octadecyl silica membrane disks modified with pentathia-15-crown-5 and determination by AAS

A simple and selective method for rapid and efficient concentration and determination of μg l⁻¹ levels of Au(III) ions in aqueous solution using octadecyl silica membrane disks modified by pentathia-15-crown-5 and flame atomic absorption spectrometry is presented. The influence of flow rates of eluent and sample solution, amount of ligand, types and least amount of eluent for elution of Au from disks were investigated. Break through volume and limit of detection of the membrane disks modified by 5 mg of the thiacrown ether was found to be 2.0 l and 1.0 μg l⁻¹, respectively. The effects of various cationic interferences on percent recovery of gold were studied. The method was successfully applied for the determinations of gold in some pharmaceutical samples and for the recovery of trace Au³⁺ ions from synthetic and water samples.