MgCl_2晶型对丙烯聚合MgCl_2载体催化剂活性的影响

ＭｇＣｌ_２晶型对丙烯聚合ＭｇＣｌ_２载体催化剂活性的影响张明辉，肖世镜中国科学院化学研究所，北京，１００８０）关键词丙烯聚合、ＭｇＣｌ２、载体催化剂近年来，有关ＭｇＣＩ。载体催化剂的研究报道和综述文章不少，但涉及载体晶型对催化剂结构性能的影响却少见．...     

吸附态物种表面迁移对程序升温脱附的影响

利用ＭｏｎｔｅＣａｒｌｏ（ＭＣ）方法研究了吸附态物种表面迁移对程序升温脱附谱图的影响。在ＭＣ模型中，催化型表面用一个二维的二方格网张表示，网络格点表示吸附活性位。     

负载型纳米非贵金属催化剂上CO的氧化

用电弧等离子体法制备了纳米Ｃｕ、Ｃｒ、Ｍｎ、Ｆｅ、Ｎｉ、采用机械方法将其加到Ａｌ２Ｏ３载体上，制成负载型纳米催化剂，用ＴＥＭ、ＳＥＭ、ＸＲＤ、ＨＲＴＥＭ等手段，对纳米粒子和催化剂进行了表征，对ＣＯ催化化的结果表明，铜催化剂的活性最高；铜、铬催化剂的活性高于贵金属钯催化剂；锰催化剂活性与钯相当；铁、镍催化剂活性较差，ＸＲＤ实验表明，催化反应后，纳米金属将变成氧化物。     

茂金属催化剂分子“剪裁”新型异氰酸酯类聚合物

报导了用茂金属催化剂Ｃｐ‘ＭＣｌ２Ｌ或Ｃｐ’ＭＣｌＬ引发异氰酸酯活性聚合的研究及发展。讨论了催化剂的分子设计，可“剪裁”具有星型，梳型，间断蠕虫链，刚－柔－刚多嵌段及具有光学活性和液晶特性的新型异氰酸酯聚合物。同时还讨论了聚合反应和催化的动力学与链增长机理。     

负载型纳米非贵金属催化剂上CO的氧化 Ⅰ.纳米催化剂活性组分的制备、表征与筛选

用电弧等离子体法制备了纳米Ｃｕ、Ｃｒ、Ｍｎ、Ｆｅ、Ｎｉ，采用机械方法将其加到Ａｌ２Ｏ３载体上，制成负载型纳米催化剂．用ＴＥＭ、ＳＥＭ、ＸＲＤ、ＨＲＴＥＭ等手段，对纳米粒子和催化剂进行了表征．对ＣＯ催化氧化的结果表明，铜催化剂的活性最高；铜、铬催化剂的活性高于贵金属钯催化剂；锰催化剂活性与钯相当；铁、镍催化剂活性较差．ＸＲＤ实验表明，催化反应后，纳米金属将变成氧化物．     

CuY和Cu－ZSM－5催化剂上NO直接分解活性及活性中心的研究

研究了ＣｕＹ，Ｃｕ－ＺＳＭ－５分子筛制备条件对ＮＯ直接分解活性的影响．结果表明，在不同酸碱度下交换的ＣｕＹ分子筛，在ｐＨ＝９时活性较好，而Ｃｕ－ＺＳＭ－５型在ｐＨ＝７时较好．随交换度提高，Ｃｕ－ＺＳＭ－５活性上升，而ＣｕＹ交换度达４５％后活性趋于平稳：用ＤＴＡ，ＴＰＤ，ＸＰＳ及ＩＲ等技术，对活性中心进行了研究，表明钢是以水合离子形式与分子筛中Ｎａ＋进行交换．Ｃｕ－ＺＳＭ－５的活性位单一，ＣｕＹ上则有两种ＮＯ吸附位．经４００℃焙烧后，铜优先占据Ｙ的β笼，此即活性位．未经焙烧的样品中铜主要以Ｃｕ２＋存在．４００℃抽空处理产生Ｃｕ＋．讨论了ＮＯ在含铜样品表面的反应过程．     

由Mg(nBu)2制备的MgCl2载体催化剂的烯烃聚合动力学

讨论了催化剂ＣＤ，ＣＭ和ＣＤ－Ａ的乙烯和丙烯聚合动力学曲线，只有催化剂ＣＤ在丙烯聚合时加入外给电子体其动力学曲线为上升－衰减型，其它均为衰减型，催化剂ＣＤ丙烯聚合活性高于催化剂ＣＭ。丙烯聚合时加入外给电子体使总活性中心浓度降低，但等规中心浓度反应增加。同种载体制备的催化剂ＣＤ和ＣＤ－Ａ载钛过程中加入内给电子体，可使其聚合活性增加，在一定范围内，随Ａｌ／Ｔｉ增加，在一定范围内，随Ａｌ／Ｔｉ增加，催化     

MZrO3（M=Ba,Sr,Ca）水热合成中结构与反应活性的关系

ＭＺｒＯ_３（Ｍ＝Ｂａ，Ｓｒ，Ｃａ）水热合成中结构与反应活性的关系郑文君，庞文琴（吉林大学化学系，长春，１３００２３）关键词水热合成，ＭＺｒＯ_３（Ｍ＝Ｂａ，Ｓｒ，Ｃａ），结构，反应活性钙钛矿型复合氧化物ＭＺｒＯ３（Ｍ＝Ｂａ，Ｓｒ，Ｃａ）是重要的功能陶...     

掺杂CaTiO3体系上甲烷氧化偶联反应的研究

受主杂质ＭＬｉ＾＋，Ｍｇ＾２＋，Ａｌ＾３＋）部分替代ＣａＴｉＯ３中Ｔｉ＾４＋形成的ＣａＴｉ０．９Ｍ０．１Ｏ３－δ具有的类似ＣａＴｉＯ３的正交晶格结构。掺杂元素的价态变化与样品的ｐ型导电性、活泼氧化物种的形成及甲烷氧化偶联（ＯＣＭ）的活性之间有着规律性的依赖关系，即随掺杂元素价态降低，ｐ型导电性增强，活泼性之间有着规律性的依赖关系，即随掺杂元素价态降低，ｐ的ｐ型电导电最大，它的ＯＣＭ性能也最好，其甲     

甲基丙烯酸三苯基甲酯与甲基丙烯酸甲酯光学活性共聚物的结构特征

采用１３Ｃ－ＮＭＲ，ＩＲ及ＷＡＸＳ表征了甲基丙烯酸三苯基甲酯（ＴｒＭＡ）与甲基丙烯酸甲酯（ＭＭＡ）光学活性共聚物结构．阐明了具有单向螺旋链的光学活性共聚物组成的非均一性及其光学活性随组成变化呈ｓ型曲线的特征．     

高效液相色谱法同时测定牛肉及其制品中敌草隆、绿麦隆的残留量

介绍了用高效液相色谱同时测定牛肉及其制品中脲类除草剂——敌草隆、绿麦隆残留量的方法。色谱柱为ＳｅｌｅｃｔｏｓｉｌＣ１８柱,流动相为甲醇－水（６０∶４０,Ｖ／Ｖ）,ＵＶ－２４５ｎｍ检测。最小检测量：敌草隆为０．４ｎｇ,绿麦隆为０．５ｎｇ。线性范围均为０．０５～１０ｍｇ／Ｌ。回收率：敌草隆为８７．３４％～８７．６４％,绿麦隆为８８．７８％～９１．９４％。     

Development of Polarization Fluoroimmunoassay for the Detection of s-Triazine Herbicides

Abstract

A rapid, non-isotopic polarization fluoroimmunoassay (PFIA) for the monitoring of the simazine (striazine herbicide) level in water was developed. Polyclonal antiserum was raised in rabbits by immunization with simazine – Keyhole Limpet Haemocyanin conjugate. Sensitivity of the PFIA with the use of heterologous tracer with the shortest bridge between antigen and fluorescein proved to be the highest. All analytical criteria for PFIA were satisfied. The detection limit of simazine (3 ng/ml in 50 μl of sample) was comparable to that for liquid or gas chromatography method. The detection limit of ELISA using the same antiserum and conjugate derivative of atrazine with horseradish peroxidase was 0.1 ng/mL of simazine. The cross-reactivity for PFIA with widely used s-triazine herbicides: atrazine, propazine, terbuthylazine was 100%, 32% and 20%, respectively. The cross-reactivity for PFIA with some metabolites of s-triazines and other herbicides was negligible.     

Sorption of copper by suspended particulate matter

The sorption of copper by suspended particulate matter from river water was investigated as a function of pH and solids concentration. Water was collected from the Delaware River and particulate matter was concentrated using Tangential-Flow Filtration (TFF). The adsorption of copper increased with increasing pH until pH 9.0. A decrease in copper adsorption was found for higher pH values. The adsorption of copper was greater for the samples with added copper than for the suspension for which no metal was added. An increase of copper adsorption proportional to particulate matter concentration was also observed. At both pH 6.0 and 7.0, there was a decrease in the adsorption of copper with increasing copper concentration.     

SPME Analysis of Potential Attractants for Palm Weevils

Abstract

Solid-phase microextraction was applied for the analysis of a mixture of potential attractants for palm weevils, constituted by seven organic compounds. Various fibers, coated with different sorbent phases, were used in this study and the best results were obtained with the polydimethylsiloxane (PDMS)/divinylbenzene (DVB) and the Carboxen/PDMS fibers. A waiting time of 5 min before sampling was adequate for sample homogenisation and a sampling time of 30 min was used to obtain good extraction efficiencies. A complete desorption of the analytes into the injection port of the gas chromatograph was achieved with an injection time of 1 min. The detection limit of the method ranged from 0.29 to 156 ng/ml for the different components of the mixture, with a lower detection limit for the compounds with higher affinity for the fiber coating. This method was used in the analysis of volatiles released from a diffuser filled with the attractant mixture.     

A sol-gel-modified poly(methyl methacrylate) electrophoresis microchip with a hydrophilic channel wall

A sol-gel method was employed to fabricate a poly(methyl methacrylate) (PMMA) electrophoresis microchip that contains a hydrophilic channel wall. To fabricate such a device, tetraethoxysilane (TEOS) was injected into the PMMA channel and was allowed to diffuse into the surface layer for 24 h. After removing the excess TEOS, the channel was filled with an acidic solution for 3 h. Subsequently, the channel was flushed with water and was pretreated in an oven to obtain a sol-gel-modified PMMA microchip. The water contact angle for the sol-gel-modified PMMA was approximately 27.4 degrees compared with approximately 66.3 degrees for the pure PMMA. In addition, the electro-osmotic flow increased from 2.13x10(-4) cm2 V(-1) s(-1) for the native-PMMA channel to 4.86x10(-4) cm2 V(-1) s(-1) for the modified one. The analytical performance of the sol-gel-modified PMMA microchip was demonstrated for the electrophoretic separation of several purines, coupled with amperometric detection. The separation efficiency of uric acid increased to 74,882.3 m(-1) compared with 14,730.5 m(-1) for native-PMMA microchips. The result of this simple modification is a significant improvement in the performance of PMMA for microchip electrophoresis and microfluidic applications.     

On-Line Preconcentration and Simultaneous Determination of Cu and Mn in Water Samples Using a Minicolumn Packed with Sisal Fiber by MIP OES

An on-line preconcentration system for the simultaneous determination of Copper (Cu) and manganese (Mn) in water samples was developed and coupled to a microwave-induced plasma optical emission spectrometer (MIP OES). The flow injection system was designed with a minicolumn packed with sisal fiber (Agave sisalana). A multivariate experimental design was performed to evaluate the influence of pH, preconcentration time, and eluent concentration. Optimal conditions for sample preparation were pH 5.5, preconcentration time was 90 s, and HCl 0.5 mol L⁻¹ was the eluent. The main figures of merit were detection limits 3.7 and 9.0 µg L⁻¹ for Cu and Mn, respectively. Precision was expressed as a relative standard deviation better than 10%. Accuracy was evaluated via spiked recovery assays with recoveries between 75–125%. The enrichment factor was 30 for both analytes. These results were adequate for water samples analysis for monitoring purposes. The preconcentration system was coupled and synchronized with the MIP OES nebulizer to allow simultaneous determination of Cu and Mn as a novel sample introduction strategy. The sampling rate was 20 samples/h. Sisal fiber resulted an economical biosorbent for trace element preconcentration without extra derivatization steps and with an awfully time of use without replacement complying with the principles of green analytical methods.     

ma-异氰酸酯改性app及其在lldpe中耐水性的评价

依次用密胺(MA)、2,4-甲苯二异氰酸酯(TDI)对聚磷酸铵(APP)进行改性,并分别应用于低密度线性聚乙烯(LLDPE)中。分别用APP在水中的溶解度变化,APP处理的LLDPE水浸后的极限氧指数(LOI)变化和磷含量变化评价了APP的耐水性。结果发现,改性后的APP在水中的溶解度减小,未改性APP的溶解度是0.368 0,MA-TDI-APP是0.212 3,减小了42.3%。改性后APP处理的LLDPE水浸后的LOI变化量减小,添加量均为30%时,未改性APP处理的LLDPE的LOI值降低了5.3%,AM-TDI-APP处理的LLDPE的LOI值降低了2.5%。改性后APP处理的LLDPE水浸后磷含量损失降低,不同APP添加量的LLDPE,未改性APP处理的磷含量损失均在6.5%以上,MA-TDI-APP处理的磷含量损失在4%以下。用扫描电子显微镜观察了改性前后APP与LLDPE的相容性,改性后的APP与LLDPE的相容性较好,MA-TDI改性的APP与LLDPE的相容性最好。     

高效液相色谱-电化学检测法测定脑组织中鬼臼甲叉甙

报道了用甲醇－水－乙酸（５６４１３,体积比）为流动相,在ＨｙｐｅｒｓｉｌＯＤＳ柱上以愈创木酚甘油醚为内标,采用电化学检测器（ＥＣＤ）测定人体脑组织中鬼臼甲叉甙含量。回收率９２．８７％,最低检测浓度为０．１ｍｇ／Ｌ,鬼臼甲叉甙在０．１～１０．０ｍｇ／Ｌ范围内呈线性,工作电压０．７０Ｖ。同时还对脑瘤患者脑组织中正常部位和肿瘤部分中鬼臼甲叉甙含量进行了测定。     

Determination of antihyperglycemic biguanides in serum and urine using an ion-pair solid-phase extraction technique followed by HPLC-UV on a pentafluorophenylpropyl column and on an octadecyl column

An HPLC-UV method was established for the determination of metformin and buformin in biological fluids. Metformin was not retained on particles packed in conventional solid-phase extraction cartridges; in contrast, buformin was retained too firmly and not eluted with a solvent for recovery. However, both drugs were retained on particles that had been treated with an ion-pair reagent of heptanesulfonate or dodecylsulfate and recovered almost completely. The recovered fraction was subjected to HPLC on a pentafluorophenylpropyl column which was suitable for the determination of both biguanides in serum and in urine. Limits of quantitation were low enough for clinical use, and reproducibility was high with an RSD of 0.9-2.3%. HPLC on a conventional octadecyl column was suitable only for the determination of buformin in serum since interfering peaks appeared on the chromatograms of urine samples. The method was applied to analysis of some clinical specimens.     

气相色谱-质谱法测定富硒酵母中的硒蛋氨酸

建立了气相色谱-质谱（GC-MS）测定富硒酵母中硒蛋氨酸含量的方法。比较了3种从样品中提取硒蛋氨酸方法的效果。样品在三羟甲基氨基甲烷（Tris）缓冲液中酶解24 h后,以丁醇及三氟乙酸酐为衍生化试剂对硒蛋氨酸进行衍生化,采用选择离子模式对衍生物进行GC-MS测定。硒蛋氨酸的回收率为98.5%~103.7%,相对标准偏差为0.9%~2.4%,检出限为0.5 mg/L（S/N=3）。对实际样品进行测定,得到样品中硒蛋氨酸的含量结果。该法简便快速,准确可靠,灵敏度高。