酶联免疫吸附分析法测定土壤试样中的阿特拉津

报道一种高灵敏度，高重现性的酶联免疫吸附分析法（ＥＬＩＳＡ）对土壤试样中阿特拉津的测定。测定的线性范围为０．０５￣５．０μｇ／Ｌ，由１４条标准曲线求得的最低检出限在０．０１８￣０．２４μｇ／Ｌ之间，线性相关系数ｒ＝０．９９２２。加标土样分别用含水甲醇和含水乙腈提取的效率都接近１００％，提取液用重蒸水１：２００稀释后可消除基质效应和溶剂效应的影响，加标平均回收率为９９．６％。     

茚三酮缩7—氨基—8—羟基喹啉—5—磺酸催化荧光测定痕量钒（Ⅴ）及其…

合成了新型席夫碱类试剂茚三酮缩７－氨基－８－羟基喹啉－５－磺酸，建立了该剂催化荧光测定痕量钒的 新体系，反应在盐酸体系中进行，其λｅｘ／λｅｍ为３２５／４４８（ｎｍ），钒（Ⅴ）的量在０－４０．０μｇ／Ｌ、４０．０－１６０．０μｇ／Ｌ呈良好线性关系，检测下限为１．７μｇ／Ｌ，方法用于水样痕量钒的测定，结果令人 满意。     

在线流动注射螯合树脂预富集石英缝管增敏火焰原子吸收法测定水中痕量铅

应用高效的在线流动注射螯合树脂预富集石英缝管增敏火焰原子吸收系统直接测定水呈痕量铅。实验用内装２００ｍｇＡｍｂｅｒｌｉｔｅＸＡＤ－４键合的５－磺酸－８羟基喹啉螯合树脂的锥形柱,在ＰＨ９条件下样品流速为８．０ｍＬ／ｍｉｎ,９０ｓ采样,用０．５ｍｏｌ／Ｌ Ｈｃｌ洗脱,在分析速度为３０样／ｈ,获得３６倍的富集,经石英缝管增敏,灵敏度提高达１１５倍,线性范围为０－２００μｇ／Ｌ,检出限为１μｇ／Ｌ。铅含量水平５０μｇ／Ｌ的水样连续测定１１次的相对标准偏差２．５％,可直接测定水体中μｇ／Ｌ级的铅。     

单扫描极谱法连续测定人发中的微量元素锌铁锰铜

本提出在０．１５ｍｏｌ／Ｌ乙二胺－７．５×１０＾－３ｍｏｌ／Ｌ三乙醇胺－２．５×１０＾－２ｍｏｌ／Ｌ硫氰酸钾底液中单扫描极谱法测定锌、铁、锰，续加硫酸（０．３ｍｏｌ／Ｌ）测定铜的方法，峰电位分别为－１．４２Ｖ，－１．６３Ｖ，－１．７１Ｖ，－０．４８Ｖ（ｖｓ．ＳＣＥ），线性范围：０．０５～１．４μｇ／ｍＬＭｎ，０．０４～１μｇ／ｍＬＣｕ，最低检出浓度．０３，０．０５，０．０２，０．０４μｇ／ｍＬＭ     

氢化物发生电感耦合等离子体原子发射光谱法同时测定水和生物样品中…

研究了一种小型同心氢化物发生配置一个气液分离器后与多道ＩＣＰ－ＡＥＳ联用，同时测定水和生物样品中砷、铋、锑、硒的方法。检出限为砷０．４μｇ／Ｌ，铋０．５μｇ／Ｌ，锑１．４μｇ／Ｌ，硒０．５μｇ／Ｌ，相对标准偏差为砷２．７％，铋１．５％，锑２．７％，硒１．９％。用本法测定美国和国家标准物质中的氢化元素，结果满意。     

丁基罗丹明B—钼酸盐光度法连续测定铈和钪

在聚乙烯醇（ＰＶＡ）存在下，丁基罗丹明Ｂ（ＢＲＢ）分别与铈钼、钪钼杂多酸络阴离子形成离子缔合物，其最大吸收均位于５７０ｎｍ，表面摩尔吸光度分别为εＣｅ＝３．９６×１０＾６Ｌ．ｍｏｌ＾－１．ｃｍ＾－１，εＳｃ＝４．７１×１０＾５Ｌ．ｍｏｌ＾－１．ｃｍ＾－１，服从比耳定律范围分别为０－２４μｇ／Ｌ Ｃｅ和０－６０μｇ／ＬＳｃ，测定极限为Ｃｅ１．０μｇ／Ｌ（ｎ＝１２）和Ｓｃ１．９μｇ／Ｌ（ｎ＝１０），对     

水杨基荧光酮—过氧化氢催化动力学光度法测定痕量锇（Ⅳ）

在碱性介质中，痕量锇（Ⅳ）对水杨基荧光酮（ＳＡＦ）与过氧化氢的氧化还原反应有显著的催化作用。本文以此为基础，提出用分光光度催化动力学测定痕量锇（Ⅳ）的新方法。本法未加掩蔽剂时的线性范围是０．０８－０．８０μｇ／Ｌ，加入掩蔽剂后的线性范围是０．０８－０．８０μｇ／Ｌ，检出限为０．０８μｇ／Ｌ。本法用于实际样品中Ｏｓ（Ⅳ）的测定，结果良好，本实验还测定了此催伦反应的活化能和反应级数。     

固氮蓝藻分离富集石墨炉原子吸收光谱法测定痕量Cr（Ⅵ）／Cr（Ⅲ）

本文选取固氮蓝藻分离富集Ｃｒ（Ⅵ）／Ｃｒ（Ⅲ），用墨炉原子吸收光谱法测定。结果表明该方法对１０ｍＬ试样，测定Ｃｒ（Ⅵ）的检测限为０．１μｇ．Ｌ＾－１＇变异系数为３．２％，在０－４５μｇ．Ｌ＾－１范围内线性关系好；测定Ｃｒ（Ⅲ）的检测限为０．３μｇ．Ｌ＾－１、变异系数３．７％，在０－４０μｇ．Ｌ＾－１范围内线性关系好。方法选择性高、富集率高。测定矿泉水、海水及自来水中的铬，获得满意结果。     

2,3—二氨基萘荧光分光光度法测定环境水样中的痕量亚硝酸盐

本文描述了用２，３－二氨基萘荧光分光光度法测定水样中亚硝酸盐的最佳测定条件，并测定了井水和湖水中的亚硝酸盐，测定样品的检出限为０．４μｇ／Ｌ，线性范围是１．０－１５００μｇ／Ｌ相对标准偏差为１．６％，加标回收率为９５％－１０６％。本法简便，快速，准确度高，共存离子干扰小，样品无须萃取步骤。     

锑（锡）—Ferron—Se（Ⅳ）络合吸附催化波研究及应用

在ｐＨ１．８的Ｈ２ＳＯ４－ＮａＡｃ缓冲溶液中，用单扫示波极谱法，Ｓｂ（Ⅲ）或者（Ｓｎ（Ⅳ）－７－碘－８－羟基喹啉－５－磺酸－Ｓｅ（Ⅳ）体系可产生灵敏的络合吸附催化波。锑、锡浓度分别在０．４～２００μｇ／Ｌ和０．８～１８０μｇ／Ｌ范围内与峰高呈线性关系，检测限分别为０．２μｇ／Ｌ和０．４μｇ／Ｌ，并用于工业废水，地下水和天然水中痕量锑和锡的测定，同时对电话性络合物的组成，极谱波的性质和电极过程机理也     

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.     

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.     

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.     

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.     

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.     

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.