氢化物－气相色谱的元素光度检测器

研究开发的一种新型的元素光度检测器主要用于锗、砷、锡和锑的氢化物气相色谱检测，具有高灵敏，高选择性。它是在普通火焰光度检测器的基础上加装了特制的滤光片改制而成的。对锗、砷、锡和锑的检测限分别为３．０×１０￣（－１１）ｇ、７．０×１０￣（－１１）ｇ、７．０×１０￣（－１０）ｇ和１．１×１０￣（－８）ｇ，相对标准偏差分别为１．８％、２．４％、２．６％和３．０％。     

氢化物－气相色谱的元素光度检测器

 研究开发的一种新型的元素光度检测器主要用于锗、砷、锡和锑的氢化物气相色谱检测，具有高灵敏，高选择性。它是在普通火焰光度检测器的基础上加装了特制的滤光片改制而成的。对锗、砷、锡和锑的检测限分别为３．０×１０￣（－１１）ｇ、７．０×１０￣（－１１）ｇ、７．０×１０￣（－１０）ｇ和１．１×１０￣（－８）ｇ，相对标准偏差分别为１．８％、２．４％、２．６％和３．０％。     

离子交换分离－氢化物原子吸收光谱法测定紫铜中微是量硒

采用阳离子交换树脂离子分离铜，发生氢化物原子吸收光谱法测定硒。上柱溶液酸度在０～７％，硒的回收率在９６～１０１％，过柱溶液中铜的浓度低于０．０１μｇ／ｍＬ。方法检出限为５×１０￣（－５）％，分析紫铜中４．４×１０￣（－４）％的硒，相对标准偏差为３％。     

HP－50＋大口径毛细管气相色谱法测定水果中多种有机氯农药残留量

以ＨＰ－５０＋大口径毛细管柱为分离柱，ＧＣ－ＥＣＤ测定水果中１４种有机氯农残。方法的检测限为０．１×１０￣（－９）～２．０×１０￣（－９），回收率范围在８８．６％～１０５．８％，变异系数２．６％～１０．５％。样品前处理采用微量化学法。     

因子分析－导数分光光度法同时测定混合物中多组分的研究

采用目标因子分析技术与导数光度法相结合，同时测定镍、铜、锌。用ＰＡＲ作显色剂，三种离子在一阶导数光谱最大吸收波长处的摩尔吸光系数分别为３．８×１０￣５，２．７×１０￣５和５．５×１０￣５Ｌ·ｍｏｌ￣（－１）·ｃｍ￣（－１）比基本光谱最大吸收波长处的摩尔吸光系数分别提高５．８、７．１和５．７倍。用于人工合成样的分析，结果良好。     

鲁米诺-双氧水-铬(Ⅲ)化学发光体系测定化探样品中痕量砷

用鲁米诺－双氧水－铬（Ⅲ）化学发光体系结合巯基棉对Ａｓ（Ⅲ）的富集分离，建立了快速的测定化探样品中痕量砷的新方法，检测线性范围为１．０×１０－４～１．０×１０１ｍｇ／Ｌ，检出限为３．４×１０－５ｍｇ／Ｌ。用于实际化探样品测定，相对标准偏差为５．５％～９．０％。     

砷锑钨杂多酸络合吸附波的研究及其分析应用

研究并建立了砷锑钨三元杂多酸体系导数示波极谱测定微量砷的新方法。在硫酸（１．０ｍｏｌ／Ｌ）－丙酮（２５％）溶液中，于５０℃，Ａｓ（Ｖ）和Ｓｂ（Ⅲ）及Ｗ（Ⅵ）形成具有电活性的砷锑钨三元杂多酸；在硫酸（０．４ ｍｏｌ／Ｌ）－丙酮（１０％）介质中，于－０． ３７ Ｖ（ｖｓ ＳＣＥ）产生一灵敏的还原峰，灵敏度比同类方法提高 １０倍。其二次导数电流峰高（ｉｐｎ）与砷量在 ５． ３ × １０－９～５． ３×１０－７ｍｏｌ／Ｌ范围内呈线性关系。相关系数（ｒ）和检出限分别为０．９９９８和２．８×１０－９ｍｏｌ／ＬＡｓ（Ｖ）。已用于高温合金（经蒸馏分离）和饮用水样（不须分离）中微、痕量砷的测定，结果满意。文中还详细研究了该杂多酸的电化学行为、络合性、电流特性和电极反应机理．     

混合粘合剂碳糊电极的制备及分析应用 Ⅱ.氯硝安定的溶出伏安法测定

本文提出用丙三醇－液体石腊混合粘合剂碳糊电极阴极溶出伏安法测定氯硝安定。在ｐＨ９．５的ＮＨ＿３－ＮＨ＿４Ｃｌ缓冲溶液中，氯硝安定在碳糊电极上于－０．７３Ｖ（Ｐ＿１）和－１．３３Ｖ（Ｐ＿２）处产生两个阴极溶出峰，利用Ｐ＿１峰可测定微量的氯硝安定。在８．０×１０￣（－８）～１．１×１０￣（－５）ｍｏｌ／Ｌ范围内，波高与浓度线性关系良好，检测Ｔ１民达４．０×１０，８ｍｏｌ／Ｌ。该法用于血清中氯硝安定测定，相对误差在１０％以内。     

高锰酸钾－抗坏血酸化学发光体系测定抗坏血酸

本文研究了高锰酸钾－抗坏血酸化学发光体系，建立了测定抗坏血酸的化学发光分析新方法。线性响应的浓度范围为５．０×１０￣（－７）ｍｏｌ／Ｌ～４．０×１０￣（－５）ｍｏｌ／Ｌ检出限为３．０×１０￣（－７）ｍｏｌ／Ｌ对２．５×１０￣（－６）ｍｏｌ／Ｌ抗坏血酸进行１０次平行测定，相对标准偏差为１．６％。考察了２２种物质的干扰情况。用于维生素Ｃ片剂及注射液中抗坏血酸含量测定，结果令人满意。     

锗（Ⅳ）─苯基荧光酮体系差分脉冲吸附伏安法的研究

在１．４１×１０－２ｍｏｌ／Ｌ的硫酸介质中，锗与苯基荧光酮试剂反应在－０．５７Ｖ（ＶＳ．ＳＣＥ）电位处产生灵敏的络合吸附波．用差分脉冲极谱法测定．该络合吸附波的峰高与锗（Ⅳ）浓度在３．２×１０－８ｍｏｌ／Ｌ－４．０×１０－７ｍｏｌ／Ｌ范围内成正比，检测下限是８．５×１０－９ｍｏｌ／Ｌ．本文详细讨论了测定的最佳条件及电极反应的机理，并用该法测定了人参中锗的含量。     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.