痕量分析中的流动注射法

本文讨论了流动注射分析(FIA)技术在痕量分析中的突出优点,阐述了该技术在痕量分析领域中的应用。文中介绍的流动注射原子光谱分析、流动注射在线分离和浓集技术、流动注射催化动力学方法以及流动注射化学发光、生物发光分析等在痕量分析中具有广阔的发展前景。     

流动注射化学发光分析研究与应用进展

评述近年来流动注射化学发光分析法的最新进展。总结了流动注射化学发光中重要的化学发光试剂及其相应的新发光体系,概述了流动注射化学发光分析与特定的检测技术、分离技术结合形成的分析体系及其应用。     

流动注射-导数火焰原子吸收光谱测定植物油中的镍、锰、铬和铅

提出了流动注射－导数火焰原子吸收光谱测定植物油中微量镍、锰、铬和铅的新方法，流动注射进样技术克服了常规火焰原子吸收法耗样量大和基体干扰严重的缺点，导数技术应用于火焰原子吸收可提高方法的灵敏度和信号的选择性，流动注射与导数技术相结合应用于火焰原子吸收成功地测定了常规火焰原子吸收法和流动注射－火焰原子吸收法难以测定的植物油中微量镍、锰、铬和铅。镍、锰、铬和铅的特征浓度（μg/mL)，分别为0.0054、0.0034、0.0067、0.025，相对标准偏差在0.3%-2.8%的范围内。     

微波炉在流动注射体系中的在线应用

微波炉在流动注射体系中的在线应用是近１０年来发展的一项新技术，在样品的在线分解和加速流动注射分析中指示反应速度方面获得广泛应用。本文从仪器技术、结果和应用几个方面概述了从１９８６年以来这项技术的发展。     

新的流动注射分析技术测定沉积物中铝

新的流动注射分析技术测定沉积物中铝赵珍义（辽宁大学化学系，沈阳１１００３６）流动注射分析（ＦＩＡ）由于具有分析速度快，精密度高，耗样量少，设备简单等特点而被广泛用于分析测试领域［１，２］。但到目前为止，对此项技术的灵敏度研究工作却甚少。本文提出了一种...     

Ce(Ⅳ)-连二亚硫酸钠-左炔诺孕酮化学发光体系的研究

1 引言 左炔诺孕酮（levonorgestrel，LNG）是一种甾体激素避孕药。目前测定左炔诺孕酮的方法，有色谱法、荧光法、光度法及放射免疫法。这些方法有的灵敏度低，有的操作繁琐。利用流动注射化学发光分析法测定左炔诺孕酮，未见报道。本实验发现，在硝酸介质中，Ce（Ⅳ）氧化连二亚硫酸钠产生较弱的化学发光，左炔诺孕酮可以显著增强此发光。在此基础上，结合流动注射技术，建立了测定左炔诺孕酮的流动注射化学发光新方法，并用于测定片剂中左炔诺孕酮含量，结果满意。     

流动注射在线离子交换预富集-氢化物发生原子荧光光谱法测定痕量碲的研究

研究了流动注射在线离子交换预富集及在线氢化物发生法与原子荧光光谱法的联用技术。设计了双柱交替正向富集和反向洗脱的在线离子交换流路系统。在采样频率为３０次／ｈ下，灵敏度较常规流动注射氢化物发生原子荧光光谱法提高１１倍。应用于环境水样中痕量碲的分析，获得了满意的结果。     

流动注射pH梯度技术－卡尔曼滤波分光光度法同时测定铜钴镍多元混合物

流动注射ｐＨ梯度技术－卡尔曼滤波分光光度法同时测定铜钴镍多元混合物毛东森，张国莹，陈同岳（上海工业大学化学化工系，上海，２０００７２）关键词：流动注射分析，梯度技术，卡尔曼滤波，分光光度法，同时测定探索不经任何分离而同时测定多个相互干扰组分混合物的分...     

流动注射-毛细管电泳联用及应用进展

流动注射是一种高效进样及在线溶液处理手段。毛细管电泳是一种高分离效率、高选择性的分析技术,但传统的毛细管电泳间歇式进样方式效率低且难用于过程分析,将流动注射进样技术与毛细管电泳结合,既弥补了毛细管电泳的进样缺陷,又可兼具两者的优点。有关两种技术的联用一直都在探索之中。文中对近年流动注射一毛细管电泳联用及应用研究进行了综述。     

流动注射编结反应器在线分离富集技术在原子光谱中的应用

综述了流动注射编结反应器在线富集技术在原子光谱中的研究进展,重点突出编结反应器富集的相关机理和不同富集方式的实际分析应用,并对流动注射编结反应器富集分离的应用前景进行了展望。引用文献59篇。     

四氟乙烯齐聚体的反应 四氟乙烯四、五聚体和芳香胺的反应

前已报道四氟乙烯四聚体(全氟-3,4-甲基己烯-3)(1)、五聚体(全氟-3,4-二甲基-4-乙基己烯-2)(2)和脂肪烷氧以及脂肪胺的亲核反应.本文报道化合物1,2和芳香胺如苯胺、β-萘胺的反应.由于烯烃1、2双键处于分子中间,因而当亲核试剂进攻时,双键容易发生重排,生成的末端基烯烃更具反应性,故导致一取代、二取代、三取代以及环化降解等复杂产物.     

Crystal engineering of photochromic diarylethene single crystals

Photochromic performance of diarylethene single crystals was controlled by crystal engineering using non-covalent aromatic-aromatic interactions as the directional intermolecular force. A diarylethene derivative with two pentafluorophenyl groups, 1,2-bis(2-methyl-5-pentafluorophenyl-3-thienyl)perfluorocyclopentene (1a), formed stoichiometric co-crystals with benzene (Bz) and naphthalene (Np) by aryl-perfluoroaryl interactions. Face-to-face pi-stacking interactions between the pentafluorophenyl groups of 1a and the aromatic molecules are responsible for 2:1 and 1:1 stoichiometric compositions in 1a/Bz and 1a/Np co-crystals, respectively. The diarylethene underwent thermally stable and photoreversible photochromic reactions in a homo-crystal of 1a and co-crystals 1a/Bz and 1a/Np. The absorption spectra of the photogenerated closed-ring isomers varied depending on the conformation of the diarylethene molecules packed in the crystals. The diarylethene 1a also formed 1:1 stoichiometric co-crystals with different kinds of diarylethenes, 1,2-bis(2-ethyl-5-phenyl-3-thienyl)perfluorocyclopentene (2a) and 1,2-bis[2-methyl-5-(1-naphthyl)-3-thienyl]perfluorocyclopentene (3a). Both co-crystals 1a/2a and 1a/3a showed photochromism. Although 1a, 2a, and 3a underwent efficient photocyclization reactions in their homo-crystals, highly selective photocyclization reactions of 2a or 3a were observed in the co-crystals. The selective reactions were confirmed by HPLC and X-ray crystallography. Excited energy transfers from 1a to 2a and from 1a to 3a are considered to occur and cause the selective reactions.     

Boron/nitrogen substitution of the central carbon atoms of the biphenalenyl diradical π dimer: a novel 2e-12c bond and large NLO responses

On the basis of the famous staggered biphenalenyl diradical π dimer 1, the eclipsed biphenalenyl (1a), with no centrosymmetry, was obtained by rotating a layer of 1 by 60° around its central axis. Furthermore, the central carbon atoms of 1 and 1a were substituted by boron and nitrogen atoms to form 2 and 2a with a novel 2e-12c bond. We found that the novel 2e-12c bond is formed by the electron pair of the occupied orbital of the phenalenyl monomer substituted by the nitrogen atom and the unoccupied orbital of the phenalenyl monomer substituted by the boron atom. As a result of the novel 2e-12c bond, 2 and 2a exhibit a fascinating interlayer charge-transfer transition character, which results in a significant difference in the dipole moments (Δμ) between the ground state and the crucial excited state. The values of Δμ for 2 and 2a are 6.4315 and 6.9253 Debye, clearly larger than the values of 0 and 0.0015 Debye for 1 and 1a. Significantly, the boron/nitrogen substitution effect can greatly enhance the first hyperpolarizabilities (β(0) ) of 2 and 2a with a novel 2e-12c bond compared with 1 and 1a with a traditional 2e-12c bond: 0 and 19 a.u. for 1 and 1a are much lower than 3516 and 12272 a.u. for 2 and 2a. Furthermore, the interaction energies (E(int) )of 2 and 2a are larger than those of 1 and 1a, which could be considered as a signature of reliability for the newly designed dimers. Our present work will be beneficial for further theoretical and experimental studies on the properties of molecules with the novel 2e-12c bond.     

Photochromic reactions of diarylethenes in single crystals with intermolecular O--H...N hydrogen-bonding networks

The crystal structures and photochromic performance of a single crystal of a diarylethene derivative possessing carboxyl groups, 1,2-bis(5-carboxyl-2-methyl-3-thienyl)perfluorocyclopentene (1 a), and cocrystals of 1 a with 4,4'-, 2,4'-, and 2,2'-bipyridines were examined. In crystal 1 a, a discrete cyclic structure was observed, in which four 1 a molecules are linked through hydrogen bonds between the carboxyl groups. In the homocrystal, photoreactive and photoinactive conformers of 1 a exist in the ratio of 1:1. In the cocrystals of 1 a with bipyridines, O--HN-type hydrogen bonds between 1 a and pyridyl groups were formed, and all 1 a molecules are fixed in a photoreactive conformation. Both the homocrystal 1 a and the cocrystals showed photochromic performances, and color variation from bluish-violet to cyan was observed, depending on the conformation of the packed diarylethene molecules.     

Controlled Dynamic Helicity of a Folded Macrocycle Based on a Bisterephthalamide with a Twofold Z‐Shaped Structure

Dynamic helicity in a folded macrocycle and control of the helical preference are described. We designed macrocycle 1 with a dual mode of folding through the integration of two flexible units that are arranged twice to form a cyclic structure. As a folding unit, we used a terephthalamide skeleton and a Z‐shaped hydrocarbon: the former acted as a control unit to induce a preference of a particular sense of dynamic helicity and the latter was just a spacer. A terephthalamide unit provided a binding site for capturing a ditopic hydrogen‐bonding guest when it adopted helically folded syn forms (M/P). Thus, only the terephthalamide unit controlled the helical sense of dynamic helicity in a folded macrocycle through the supramolecular transmission of chirality upon complexation with a chiral ditopic guest. In addition, chirality on a host could also contribute to the control of the helical preference in a folded macrocycle, which led to exceptionally enhanced chiroptical signals.     

Synthesis of well-defined polymers with protected silanol groups by atom transfer radical polymerization and their use for the fabrication of polymeric nanoparticles

Copper-mediated atom transfer radical polymerization (ATRP) of a protected silanol group-holding methacrylate, methacryloxypropyltrimethoxysilane (MOPS), was investigated. In a dry condition using carefully distilled solvent and monomer, the polymerization proceeded in a living fashion providing a low-polydispersity polymer with a predicted molecular weight. The ATRP in conjunction with the sequential monomer addition of methyl methacrylate (MMA) and MOPS afforded a block copolymer of the type PMMA-b-poly(MMA-r-MOPS). The heat treatment of a solution of the block copolymer in the presence of a catalytic amount of ammonia gave a polymeric core-shell nanoparticle with a shell of PMMA moieties and a core of the poly(MMA-r-MOPS) blocks cross-linked via the condensation of the trimethoxysilane groups of the MOPS moieties.     

Reactions of Ruthenium–Allenylidene Complexes Tethering a Cyclopropyl Group

Two cyclopropyl allenylidene complexes [Ru]=CCC(R)(C₃H₅) ([Ru]=[RuCp(PPh₃)₂], Cp=Cyclopentadienyl; R=thiophene ( 2a ) and R=Ph ( 2b )) are prepared from the reactions of [Ru]Cl with the corresponding 1‐cyclopropyl‐2‐propyn‐1‐ol in the presence of KPF₆. Thermal treatment, halide‐anion addition, and palladium‐catalyzed reactions of 2a and 2b all lead to a ring expansion of the cyclopropyl group, giving the vinylidene complexes 4a and 4b , respectively, each with a five‐membered ring. This ring expansion proceeds by C C bond formation between Cβ of the cumulative double bond and a methylene group of the cyclopropyl ring. In the reaction of 2a with pyrrole, consecutive formation of two C C bonds, one between C‐2 of pyrrole and Cγ of 2a and the other between C‐3 of pyrrole and Cα, results in the formation of 6a . The reaction proceeds by addition of pyrrole and 1,3‐proton shifts. The hydrogenation of 2a by NaBH₄ is carried out in different solvents. The cumulative double bonds are reduced regioselectively to give a mixture of 7a and 8a . Interestingly, use of different solvents leads to different ratios of 7a and 8a . Presence of a protic solvent like methanol in dichloromethane or chloroform solution increases the yield of 8a , thus revealing that both the rates of hydroboration and deboronation increase. The structures of two new complexes 4a and 6a have been firmly established by X‐ray diffraction analysis.     

Triarylborane-Appended Anils and Boranils: Solid-State Emission,Mechanofluorochromism, and Phosphorescence

Herein, the design, synthesis, optical properties, and mechanofluorochromism characteristics of a series of conjugates having covalently linked triarylborane (TAB) and anil/boranil units (TAB-anil: 1 a – 3 a and TAB-boranil: 1 – 3 ) are reported. The electronic interactions between TAB and anil/boranil in 1 a – 3 a and 1 – 3 were fine-tuned by changing the boryl moiety's position on the phenyl spacer connecting the BMes₂ (Mes=mesityl) and anil/boranil units. A boryl moiety at the meta position ( 1 a ) of the phenyl spacer stabilizes the enolic form (E-OH), whereas a boryl moiety at the para position ( 2 a and 3 a ) stabilizes the keto form (Z-NH) in the solid state. However, in solution 1 a , 2 a , and 3 a exhibit keto–enol tautomerism in both ground and excited states. Compounds 1 a – 3 a and 1 – 3 show red-shifted absorption compared with 4 a and 4 , which are devoid of TAB moieties, which indicate effective participation of an empty p orbital on the boron center in 1 a – 3 a and 1 – 3 . Compounds 1 and 2 showed fluorescence variations in response to external stimuli such as mechanical grinding. Long phosphorescence lifetimes of 18–46 ms were observed for compounds 1 – 3 . The observed optical properties of 1 a – 3 a and 1 – 3 are rationalized in the context of quantum mechanical calculations.     

Equilibrium between a vinylogous ylide and a phosphonium dienolate zwitterion: vinylogous Wittig olefination versus vinylogous aldol-type reaction

This paper describes the equilibrium established between a phosphonium dienolate zwitterion and a vinylogous phosphorus ylide, and their reactions with aldehydes. The reactions between ethyl 2-methyl-2,3-butadienoate and various aldehydes occur through either a phosphonium dienolate or a vinylogous ylide intermediate, depending on the presence/absence of a Lewis acid and the nature of the phosphine. We observed a rare vinylogous Wittig olefination from the reaction between ethyl 2-methyl-2,3-butadienoate and an electron-deficient aromatic aldehyde in the presence of a stoichiometric amount of an electron-deficient triarylphosphine and a catalytic amount of a Lewis acid (e.g., BF₃·Et₂O). On the other hand, the use of triphenylphosphine, in the absence of a Lewis acid, facilitated vinylogous aldol addition, accompanied by a rare 1,2-aryl phosphorus-to-carbon migration.