流动注射在线吸发离预浓集冷蒸气原子吸收法测定痕量镉

研究了IRC－718离子交换树脂、122螯合树脂和MuromacA-1树脂对镉 的预浓集条件,建立了超痕量镉的流动注射在线吸着分离预浓集冷蒸气发生原子吸收光谱测定方法,在每小时进样60,60和45次速度下检出限（3σ）分别为3．0,3．0和2．4ng/L,线性范围0－0．3μg/L,对0．2μg/L镉测定的相对标准偏差为2．0％－2．6％（n=11),。讨论了用这3种离子交换树脂微柱进行分离预浓集时条件参数的优化、抗干扰能力以及对天然水样的回收率,并分别进行了水样的测定。     

碱性品红共振光散射法测定DNA研究

基于脱氧核糖核酸（DNA）对有机染料碱性品红的共振光散射增强效应，拟订了一种测定DNA的共振光散射法。在pH=6．75～7．25的范围内，碱性品红在594nm处的共振光散射增强与yDNA和ctDNA的浓度呈线性关系，线性范围分别为0．20～1．60μg／mL和0～1．50μg／mL，相关系数分别为0．9997和0．9994，检出限可达26．5μg／L。该方法简便、快速，用于合成样品中DNA的测定，结果满意。     

邻苯二酚紫-溴化十六烷基三甲铵-核酸共振光散射体系的研究及其分析应用

研究了核酸与阴离子染料邻苯二酚紫(PV)及阳离子表面活性剂溴化十六烷基三甲铵(CTMAB)体系的共振光散射光谱特性。在pH2．35的柠檬酸介质中，核酸(yRNA或fsDNA)与阳离子表面活性剂CTMAB对邻苯二酚紫的共振光散射光谱有协同增强作用，产生最大散射波长为400nm的共振光散射光信号。在最佳实验条件下，共振光散射测定yRNA和fsDNA的线性范围皆为0．02-0.75mg／L，检出限分别为1．4和8．7μg/L。据此建立了一种测定核酸的新方法。     

电感耦合等离子体质谱法快速测定尿、血液和头发中的铊含量

采用电感耦合等离子体质谱法快速测定了尿、血液和头发中的铊含量。以^115In作内标,方法检出限为0．0055ng·mL^-1（3δ）,标准曲线范围为1～1000ng·mL^-1（r=0．9998）,相对标准偏差为2．8％（n=10）,加标回收率在94％～104％之间。     

4种喹诺酮类药物滤纸基质室温Lin光法研究

提出了以滤纸为基质的环丙沙星、氟罗沙星、洛美沙星和氧氟沙星4种喹诺酮类药物的滤纸基质室温Lin光（PS-RTP)分析的新方法。方法取样量少（1．5μL).其线性动力学范围依次为0．11－55．2、0．35－211、2．10－526、1．03－411（ng/斑点）；灵敏度高，其检出限分别为0．082、0．070、0．080、0．123（ng/斑点）；标准回收率在97．70％－102．2％之间。相对标准偏差RSD＜1．8％。     

氢化物发生-冷阱捕获-色谱分离-原子吸收法测定天然水中砷的形态

研究建立了氢化物发生－冷阱捕获－色谱分离－原子吸收方法测定天然水中四种主要砷形态。测试系统自行组装，色谱住填料采用ChromosorbGAW－DMCS（粒径0．3～0．45mm），其上涂布3％OV－101。方法的检出限以砷计分别为：As（V）0．51ng，As（Ⅲ）0．43ng，MMA0．38ng，DMA067ng；12ng砷标准偏差As（Ⅴ）4．21％，As（Ⅲ）3．56％，MMA3．23％，DMA5．46％。在0～50ng砷量范围标准曲线线性关系良好。该法适用性广，已用于湖水、河水、海水和地下水等不同水样神形态测定，加标回收率93．5％～104．9％。给出了上述水样四种砷形态的分析结果。     

水中苯胺类化合物的分光光度法测定

提出3种测定水中苯胺类化合物的分光光度法，在氢氧化钠介质（PH＝12．2）中，邻甲氰基苯酚、8－羟基喹啉和1－萘酚均可与苯胺形成偶氮化合物，它们的最大吸收波长分别位于452、482和497nm处，与传统的N－（1－萘基）乙二胺光度法相比，这3种方法测定苯胺更方便，快速、灵敏，线性范围更宽；它们的检出下限分别为8．6、10、14μg/L；线性范围分别为0－5．6、0－4．8和0－3．2mg/L。这3种方法用于测定环境水样中的苯胺类化合物，均获得了满意的结果。     

溴代十六烷基三甲基铵敏化吡罗红B-核酸作用的共振光散射增强法测定核酸

基于表面活性剂溴代十六烷基三甲基铵（CTMAB）对吡罗红B-核酸作用的共振光散射增强效应有敏化作用,建立了一种高灵敏测定核酸的新方法。在pH7．4时,吡罗红B在328nm处的共振光散射的增强与核酸浓度有良好的线性关系。在最佳实验条件下,对小牛胸腺DNA（ct-DNA）、鲱鱼精DNA（fs-DNA）、酵母RNA（yeast—RNA）测定的线性范围分别为0．0～1．2mg／L、0．0～0．8mg／L和0．04～1．4mg／L。检出限分别为6．1μg／L、11．2μg／L和8．6μg／L。该法简便、快捷、重现性好,对合成样品进行了测定,结果令人满意。     

罗丹明6G-阴离子表面活性剂体系的共振瑞利散射光谱及分析应用

在pH2．00～3．42的B—R缓冲溶液中,罗丹明6G与十二烷基苯磺酸钠（SD—BS）、十二烷基硫酸钠（SDS）阴离子表面活性剂反应形成离子缔合物,导致共振瑞利散射（RRS）增强,并产生新的RRS光谱,最大RRS峰位于375nm,方法对SDBS、SDS的检出限分别为6ng／mL、5ng／mL,其线性范围分别为0．02～5．6μg／mL、0．02～14．0μg／mL。研究了适宜的反应条件,方法具有较高的灵敏度,用于合成水样和环境水样中阴离子表面活性剂含量的测定,结果满意。     

阻抑聚丙烯酰胺催化蛋白质-亚甲基蓝褪色光度法测定痕量铋

在加热条件下，基于Bi（Ⅲ）对聚丙烯酰胺（PAM）催化蛋白－亚甲基蓝（MB）褪色反应有强的抑制作用，建立了动力学光度法测定铋的新方法。△A与CBi(Ⅲ）呈线性关系的范围为0．08－0．48μg/L；检出限为0．004μg/L；对0．04和0．040μgBi(Ⅲ）／L测定的RSD分别为6．4％一2．6％，本阻抑－催化褪色反应对Bi(Ⅲ）、蛋白质－亚甲基蓝和PAM为一级反应，表观活化能为49．22kJ/mol.该方法已用于某些谷物，人发和水样中Bi(Ⅲ）的测定。结果满意。     

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%.     

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.     

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.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.     

Copper catalyzed/mediated synthetic methodology for ebselen and related isoselenazolones

Scope of the copper catalyzed/mediated selenium-nitrogen coupling reaction has been studied for the synthesis of isoselenazolones. It is noticed that the 2-chloro, 2-bromo-, and 2-iodo-aryl amides substrates can be exploited in the selenium-nitrogen coupling reaction by employing 25-100 mol % of CuI/1,10-phenanthroline (L) and potassium carbonate as a base in DMF. Furthermore, electron rich 2-chloro-arylamides also underwent selenium-nitrogen coupling reaction to give biologically important selenium-nitrogen heterocycles. Also, copper-catalyzed selenium-nitrogen coupling reaction has been meticulously applied for the synthesis of diaryl diselenides having methoxy, amine, and amide functionality from respective aryl iodides in the presence of stoichiometric amount of succinimide as an external Se-N coupling partner.     

Knoevenagel condensation catalyzed by novel Nmm-based ionic liquids in water

A series of novel N-methyl morpholine (Nmm) based ionic liquids with 1,2-propanediol group were synthesized and used as catalysts for Knoevenagel condensation at room temperature in water. Under the effect of the catalyst, various aldehydes or aliphatic ketones could react with a wide range of activated methylene compounds well, including malononitrile, alkyl cyanoacetate, cyanoacetamide, β-diketone, barbituric acid, 2-arylacetonitrile and thiazolidinedione. Furthermore, most of the products could be separated just by filtrating and washing with water. Additionally, the catalyst is recyclable and applicable for the large-scale synthesis.     

Construction of polyheterocyclic spirotetrahydrothiophene derivatives via sulfa-Michael/aldol cascade reaction

A series of polyheterocyclic spirotetrahydrothiophene derivatives were obtained in moderate to excellent yields via a catalyst-free sulfa-Michael/aldol cascade reaction of chalcones 1 and commercially available 1,4-dithiane-2,5-diol 2 under mild conditions. We also present the first asymmetric sulfa-Michael/aldol cascade reaction of chalcones 1 and commercially available 1,4-dithiane-2,5-diol 2 with moderate to good enantioselectivities catalyzed by readily available chiral phase-transfer catalysts (PTCs).     

Suzuki-Miyaura reactions of the soluble guanylate cyclase inhibitor NS2028: a non-product specific route to C-8 substituted analogues

Both soluble guanylate cyclase (sGC) inhibitors ODQ 1 and NS2028 2 are synthesized via improved protocols. In the former case treating 3,4-dihydroquinoxalin-2(1H)-one oxime 8, which can be prepared in two steps from 1,2-benzenediamine, with 1,1′-carbonyldiimidazole (CDI) gives the dihydro-ODQ 10 that in the presence of KMnO₄ oxidises to give ODQ 1 in an overall yield of 46% starting from 1,2-benzenediamine. In the latter case, the synthesis affords NS2028 2 from 2-amino-4-bromophenol 3 in three steps with an overall yield of 85% and avoids the need for chromatography. Furthermore, Suzuki-Miyaura reaction conditions are described that enable the preparation of 8-aryl and 8-heteroaryl derivatives of NS2028 directly from NS2028 2. Finally, demethylation of the 8-(methoxyphenyl) substituted analogues afforded the 8-(hydroxyphenyl) derivatives 40-42. All new products are fully characterised.