海水中14种有机磷农药的气相色谱测定方法

建立了毛细管气相色谱-火焰光度检测器测定海水中14种有机磷农药的方法。用CH2Cl2液液萃取pH 6~8范围内的样品,然后采用毛细管柱及火焰光度检测器进行测定。在0.005~0.3μg/mL范围,相关系数为0.9904%~0.9996%。方法检出限低和精密度高,相对标准偏差为1.71%~5.89%。该方法具有灵敏、快速、简便等特点。     

气相色谱仪双毛细管柱双检测器技术在毒物检测中的应用

利用双毛细管柱双检测器技术建立常见毒物的检验方法, 并对其进行定性分析. 样品进样后通过VSOS装置同时进入两根不同极性的毛细管柱, 经分离后到达两个不同选择性的检测器. 利用VSOS装置可对毒物进行较好的分离、定性. 该方法可对常见毒物进行准确定性.     

柱层析光纤荧光检测器测定药物中的维生素B2

1引言 维生素B2是人体不可缺乏的物质,因而引起人们的广泛关注.作者采用光纤荧光检测器于35μL的流通池中测定了经柱层析的维生素B2.其激发波长为470nm;发射波长为565nm.该光纤荧光检测器具有操作简便、快速、灵敏度和准确度高,重现性好等优点.应用该体系测定了多种药物中的维生素B2,结果令人满意.     

利用气体微量转移技术制备低含量R12气体标准物质

介绍利用气体微量转移技术快速制备低含量气体标准物质的方法原理、关键技术及过程,总结了该技术的优点.利用该方法将纯气两次稀释,得到4瓶浓度为0.1 μmol/mol的R12混合气,浓度的相对标准不确定度为0.14％.用带有电子捕获检测器的气相色谱仪对4瓶混合气量值进行一致性核验,偏差均符合要求,制备的4瓶混合气的量值具有较好的一致性.新方法通过减少制备步骤,缩短了制备时间,节约了制备成本.     

以多孔碳毡为工作电极的流动注射库仑检测器的研究及应用

本文设计了一个以多孔碳毡为工作电极的库化检测器并将其于用流动注射分析,以抗坏血酸、氢醌,没食子酸及二氧化硫为电活性物质检验该检测器的电化学特性。详细地研究了该检测器的库仑转换效率,选择性,线性范围,检测限及质量转移系数,并将该检测器作为双检测器流动注射分析系统中的“清除”电解池,用于酒中二氧化硫的测定,其结果与常规的吹气－氧化法非常吻合。     

毛细管电泳-荧光/非接触电导组合型检测器的研制

报道了一种毛细管电泳-荧光／非接触电导组合型检测器。该检测器共用非接触电导检测池,实现了双检测器响应同步。优化了非接触电导检测系统中激发电压信号及其频率;荧光检测是用发光二极管作为激发光源,用光纤收集并传输荧光信号至光电倍增管。用无机金属离子和异硫氰酸荧光素评价该体系,结果表明,该检测器达到了任一单类型检测器性能指标。     

毛细管电泳高频电导检测器的研制

设计了一种新的毛细管电泳检测器.根据高频电导滴定原理,将电导电极做成两个金属圆筒套于分离毛细管外,并向两个电极施加高频电压.经毛细管分离后的组分流过两个电极之间时,高频电流发生变化,得到毛细管电泳图.该检测器具有应用范围广、操作简便及重现性好等优点,已初步应用于混合无机离子的测定.     

毛细管电泳化学发光在线检测

评论了毛细管区带电泳化学发光检测联用技术这一新兴的研究领域。化学发光检测具有背景低、热力学范围宽、灵敏度高的优点，适于毛细管电泳柱后微量样品的在线检测。论述了该检测器与毛细管电泳联用的接口和应用状况。     

用于高效液相色谱的电化学检测器

电化学检测器是高效液相色谱检测器家族中的一员,虽然按应用数量而言它排在紫外吸收、荧光和示差折射之后,占第四位,但是由于电化学检测器的高选择性、高灵敏度和低造价等优点,发展相当迅速。据统计,在1982年前的十年中有关液相色谱电化学检测器的研究报告发表超过600篇,尤其是在生化、医学和环境分析方面的应用更为突     

电泳芯片无接触电导检测器的理论研究

目前电泳芯片大多数采用的是光学检测的方法,这为电泳芯片的微型化、一体化集成带来了一定的难度。为此,设计了一种新的电泳芯片高频无接触电导检测器,并对这种新型的检测器进行了理论研究和分析,建立了高频电导检测器等效电路模型,对高频电导检测器的结构进行了设计;综合考虑区带展宽等因素,确定了检测器的结构尺寸。该检测器具有应用范围广、结构简单、易于一体化集成的特点。     

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%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

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.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

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.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.