Bienzyme Sensor Based on an Oxygen Reducing Bilirubin Oxidase Electrode

Based on an oxygen reducing electrode combining bilirubin oxidase and multiwalled carbon nanotubes modified gold (BOD‐MWCNT‐Au electrode) a bienzyme sensor is developed. Therefore the BOD‐MWCNT‐Au electrode is covalently coupled to enzymes catalysing oxygen‐consuming reactions (glucose oxidase and ascorbate oxidase) to result in a membrane‐free bienzyme electrode. The electrochemical characterisation of these bienzyme sensors reveals an enzyme substrate sensitivity down to 250 μM glucose and 100 μM ascorbate. In addition, the assembled sensor systems allow amperometric measurements in a potential range where the influence of interfering substances reacting directly at the transducing electrode is minimised. The results indicate that the BOD electrode provides a suitable platform for sensing analytes of medical and environmental interest for which oxidases of high activity are available.     

Uncertainty of measurement for summed masses: application to controlled substances

Because sentences for drug possession depend on the mass of the seized drug, testing laboratories must often determine the summed mass of numerous items submitted under a single case. One common practice for this purpose is to continue analyzing and weighing samples until a legal threshold is passed, at which point it is important to inform the court whether the summed mass is significantly above the threshold, or only marginally so. This paper develops a means for estimating the uncertainty of the summed mass for the common situation where the readability, d, of the balance dominates the uncertainty. It is seen that for all sample sizes the uncertainty, UM, is given by the remarkable simple expression UM = (d/2) × [N + SQRT(3N)] + N × CCE, where N is the number of items and CCE is the absolute value of the calibration check error. In most instances, this can be further simplified to UM = N × d.     

Volatile Organic Compound Sensing by Quartz Crystal Microbalances Coated with Nanostructured Macromolecular Metal Complexes

We report the construction of a molecular recognition layer composed of polyelectrolyte brushes and metal complexes on the surface of a quartz crystal microbalance (QCM) and the sensing abilities for various volatile organic compounds (VOCs). Atom‐transfer radical polymerization of 2‐(dimethylamino)ethyl acrylate from an initiator‐terminated self‐assembled monolayer yielded polyelectrolyte brushes on the surface of a weight‐detectable quartz crystal microbalance. One end of a poly[(2‐dimethylamino)ethyl methacrylate] brush was covalently attached onto the surface of a sensor. We found that metallophthalocyanines with four bulky pentaphenylbenzene substituents could adsorb volatile organic compounds selectively into their cavities. Macromolecular metal complexes were prepared by immersing polymer‐brush‐modified QCMs into an aqueous solution of sterically protected cobalt phthalocyanine. Anionic cobalt phthalocyanine was trapped in the polymer brushes and acted as a molecular receptor for the sensing of VOC molecules.     

顶空气相色谱-质谱法测定玩具中的10种挥发性有机物

建立了检测玩具中10种挥发性有机物(VOC)残留量的顶空气相色谱-质谱(HS-GC-MS)方法。样品经140 ℃、45 min静态顶空后,通过DB-624色谱柱分离和质谱检测,外标法定量。该方法对于不同VOC的定量限(LOQ)均在0.66 mg/kg以下,线性范围为0.001～2.0 μg,平均回收率在79%～106%之间,相对标准偏差(RSD)在0.4%～5.6%之间。该方法具有准确灵敏、简单快速等特点,将其应用于实际玩具样品的检测取得了良好效果。     

硫酸盐还原菌分泌胞外多聚物吸附Cu2+的特性

为探讨硫酸盐还原菌胞外多聚物(EPS)吸附Cu2+的特性,采用热力学平衡实验研究了EPS对Cu2+的吸附行为,并通过红外光谱(FTIR)和带能谱仪的扫描电镜(SEM-EDS)分析EPS吸附Cu2+前后官能团以及元素组成的变化来研究EPS吸附Cu2+的机理.结果表明,硫酸盐还原菌EPS对Cu2+的吸附平衡能较好地用Fre...     

Identification and Biological Activity of Volatile Organic Compounds Emitted by Plants and Insects. IV. Composition of Vapor Isolated from Certain Species of Artemisia Plants

The components of fragrance from four wormwood species of theArtemisiaL. genus were analyzed by GC-MS. The major and minor components of volatile essential oils typical of the studied plant species were determined.     

CHEMICAL INVESTIGATIONS ON SOME HYPERICUM SPECIES GROWING IN TURKEY-I

The chemical composition of five taxa of the genusHypericumL. obtained from herbarium specimens has been investigated.Namely, H. adenotrichum Spach(endemic),H. calycinumL.,H. cerastoides(Spach) Robson,H. montbretiiSpach, andH. perforatumL. were subjected to microdistillation to isolate the volatile compounds, which were analyzed by GC/MS.     

A new family of heavy transition metal coordination compounds and its application,I. Design,synthesis and characterization of volatile organohafnium precursors

The first three representatives of a new family of volatile organohafnium compounds suitable as metallo-organic chemical vapour deposition precursors were synthesized. A combination of cyclopentadienyl and alkoxo-ligands with a bicyclo[2.2.1]heptanc framework was used. Volatility at relatively low temperatures for hafnium compounds was found and the precursors were characterized by elemental analysis and spectroscopic methods (IR, ¹H and ¹³C NMR, mass spectrometry and mass-analysed ion kinetic energy spectroscopy). The outlook for use in hafnium functional materials synthesis was derived from the fragmentation data.     

热解吸直接进样气相色谱法分析室内空气中的总挥发性有机化合物

建立室内空气中总挥发性有机化合物的热解吸直接进样气相色谱分析方法。采集的空气样品吸附于Tenax吸附管中,将吸附管置于热解吸仪上,解吸气体直接由进样阀快速进入气相色谱仪进行分析,采用非极性石英毛细管柱,氢火焰离子化检测器检测。8种组分的线性范围为0.01～11.04μg,检测限为0.001～0.006μg,测定结果的相对标准偏差RSD≤4.8%。该方法符合室内空气中总挥发性有机化合物分析的要求。     

Thermal properties of barium complexes used for depositing thin films of YBa2Cu3O7 superconductors

The thermal properties of several barium containing complexes are compared by using thermogravimetric analysis and solids probe mass spectrometry. The properties of complexes containing flourinated and non-fluorinated β-diketonates with and without the presence of a polyether to occupy additional barium coordination sites are compared. Barium complex thermal properties are heavily dependent on the structure of the β-diketones and polyether comprising the complex. Barium complexes containing fluorinated ligands are better suited for chemical vapour deposition of barium than complexes containing non-fluorinated ligands because they efficiently evolve vapours containing barium at lower temperatures.