Mass spectrometric analysis of low molecular mass polyesters by laser desorption/ionization on porous silicon

A low molecular mass polyester was analyzed by desorption/ionization on porous silicon (DIOS) mass spectrometry. The results were compared with those of matrix-assisted laser desorption ionization (MALDI) mass spectrometry using matrixes of alpha-cyano-4-hydroxycinnamic acid (CHCA) and 10,15,20-tetrakis(pentafluorophenyl)porphyrin (F20TPP). The CHCA matrix was not suitable for characterization of low molecular mass components of the polyester because the matrix-related ions interfered with the component ions. On the other hand, the F20TPP matrix showed no interference because no matrix-related ions appeared below m/z 822. However, the solvent selection for determining optimal conditions of sample preparation was limited, because F20TPP does not dissolve readily in any of the available organic solvents. In the DIOS spectra, the polymer ions were observed at high sensitivity without a contaminating ion. No matrix is needed for DIOS spectra of low molecular mass polyesters, facilitating sample preparation and selectivity of a precursor ion in post-source decay measurements.     

Iodination of alcohols using triphenylphosphine/iodine under solvent-free conditions using microwave irradiation

A straightforward and effective procedure for the conversion of benzylic, allylic and aliphatic alcohols to the corresponding iodides using Ph₃P/I₂ under solvent-free conditions using microwave irradiation is reported.     

Microwave-assisted arylation of rac-(E)-3-acetoxy-1,3-diphenylprop-1-ene with arylboronic acids

The palladium-catalyzed arylation of rac-(E)-3-acetoxy-1,3-diphenylprop-1-ene with arylboronic acids was studied under controlled microwave irradiation conditions. A variety of different catalysts, bases, and solvents were explored in order to achieve optimum yields in the shortest possible reaction times. The best isolated yields were obtained using Pd₂(dba)₃·CHCl₃/PPh₃ as the catalytic system, potassium phosphate monohydrate as the base, and toluene/H₂O as a solvent system. Microwave irradiation using 5 mol % of the palladium catalyst for 90 s (max. temp 170 °C) generally afforded the cross-coupling products in good to excellent yields.     

钛铁矿中钛的测定

利用钛铁矿能显著吸收微波的介电特性，采用家用微波炉，在微波辐照下，用浓磷酸消解矿样，并用氧化还原滴定法测定钛的含量，试验结果表明，该方法能快速分解矿样，测定结果准确，与传统分析方法比较，该法具有简便、快速、低耗、适应大批量样品分析等优点。还对钛铁矿的结构作了X-射线衍射分析。     

一种用于空气中二氧化碳现场测定的新方法

一种用于空气中二氧化碳现场测定的新方法于爱民，杨广德，王锐，金钦汉（吉林大学化学系，长春１３００２３）关键词微波诱导等离子体，离子化检测器，气相色谱仪，二氧化碳二氧化碳在植物生长代谢及其生态平衡过程中起着重要作用，现场测定二氧化碳是目前农业、环境科学...     

Do intramolecular halogen bonds exist? Ab initio calculations and crystal structures’ evidences

Cl···O intramolecular contacts are analysed here. Hence the Cambridge Structural Database (CSD) search was performed to find five-membered Cl–C=C–C=O pseudo-rings closed through Cl···O intramolecular contacts. Such rings were analysed and it was found that some of Cl···O distances are smaller than the corresponding sum of van der Waals radii. Additionally ab initio MP2/6-311++G(d,p) calculations and AIM analyses were carried out here on 3-chloropropenal and its fluoro derivatives to deepen the nature of intramolecular Cl···O interactions, some of findings may indicate that they are attractive and stabilizing ones. This paper is dedicated to Prof. T. M. Krygowski on the occasion of his 70th birthday     

Determination of Organochlorine Pesticides in Sediments from Authie Bay Using Microwave Assisted Solvent Extraction

The aim of this study was to develop an analytical method to determine the organochlorine concentrations in sediments. Combination of Microwave assisted Solvent Extraction (MASE) and capillary gas chromatography with specific detection (electron capture detector) was a viable approach for the determination of pesticides in solid matrixes. In this study, MASE development was focused on the selection of a suitable extraction solvent for all the target analytes. MASE procedure was validated by comparison with conventional methods such as Soxhlet and sonication extraction. The proposed method was then applied to determine the organochlorine insecticides concentrations in samples from Authie Bay (France). Environmental water samples were analysed and five target analytes were detected in concentrations from 0.03 to 0.56 ng/g of dry sediment. These investigations showed the accumulation and the persistency of these products in sediments in spite of the fact they were banned a few decades ago.     

毛细管电泳-电感耦合等离子体原子发射光谱法对田七提取液中Fe、Cu和Mg存在状态的研究

提出了以水作溶剂微波萃取提取,并以毛细管电泳电感耦合等离子体原子发射光谱(CE-ICP-AES)法测定田七提取液中Mg、Cu和Fe的形态的分析方法。实验结果表明:Mg仅以游离态存在;而Cu和Fe除了游离态以外,还存在其它三种未知的形态。此外,还测定了田七中20个微量元素的总含量,并得到了上述待测元素在水提取液中的提取率。     

微波照射合成不对称1，4－二氢吡啶的研究

微波照射合成不对称１，４－二氢吡啶的研究张雅文，沈宗旋，潘备，杨海康，陆新华，陆澄容（苏州大学化学系苏州２１５００６）关键词缩合，二氢吡啶，微波Ｈａｎｔｚｓｃｈ合成是制备１，４－二氢吡啶的经典方法。这一合成的改进方法之一是３－氨基巴豆酸酯与醛和乙酰乙...     

微波辅助合成发光可调ZnS∶Cu纳米晶

以巯基丙酸(MPA)为稳定剂, 利用微波辐射加热方法制备了水溶性的Cu掺杂的ZnS纳米晶. 通过改变微波条件, 可以在460～572 nm之间实现对ZnS∶Cu纳米晶发射峰位的连续调控. 通过XRD、 UV-Vis、荧光及荧光衰减对ZnS∶Cu纳米晶的结构和发光性质进行了详细探索, 并利用时间分辨荧光光谱对其发光机理进行了初步研究.