A novel thiocyanate-selective electrode based on a zinc–phthalocyanine complex

A novel thiocyanate (SCN⁻)-selective PVC membrane electrode based on a zinc-phthalocyanine (ZnPc) complex as neutral carrier is described. The membrane electrode containing ZnPc with 5.1% (w/w) ionophore, 29.2% (w/w) PVC, and 65.7% (w/w) 2-nitrophenyl octyl ether (o-NPOE) as plasticizer displayed an anti-Hofmeister selectivity sequence , and exhibited near-Nernstian potential response to thiocyanate ranging from about 1.0×10⁻¹ to 1.0×10⁻⁶ mol L⁻¹ with a detection limit of 7.5×10⁻⁷ mol L⁻¹ and a slope of 58.1±0.5 mV per decade in pH 3.0 phosphate buffer solution at 25 °C. This preferential response is believed to be associated with the unique coordination between the central metal of the carrier and thiocyanate.      

亚铁烷基咪唑自旋交叉配合物的合成及其金属有机凝胶性能

通过1-庚烷基-1H-咪唑-2-甲醛(L~1)、1-十四烷基-1H-咪唑-2-甲醛(L~2)、1-十六烷基-1H-咪唑-2-甲醛(L~3)、1-十八烷基-1H-咪唑-2-甲醛(L~4)、1-二十烷基-1H-咪唑-2-甲醛(L~5)分别和四氟硼酸亚铁与1-苯乙胺反应一步法合成了配合物1～5。利用红外光谱(IR)、元素分析(EA)手段对1～5进行表征。配合物1的X射线单晶衍射结构研究表明,每个结构基元中包含1个[Fe(L~1)_3]~(2+)阳离子和2个四氟硼酸根阴离子。铁(Ⅱ)金属中心与3个配体上的6个N原子配位,形成面式八面体单核化合物。Fe(Ⅱ)-N键长表明配合物1中的Fe(Ⅱ)在173 K时处于低自旋状态。在[Fe(L~1)_3]~(2+)中,相邻配体中的苯环和咪唑环形成分子内π-π相互作用;[Fe(L~1)_3]~(2+)进一步通过烷基链与芳香环之间的C-H…π相互作用形成超分子网络结构。磁性测试表明,配合物1表现出不完全的自旋交叉性能,转换温度为341 K;2为高自旋顺磁性化合物,3～5则表现出不完全的自旋交叉行为。以具有较长烷基链的配合物2～5作为凝胶因子,环己烷作为溶剂可形成对应的金属有机凝胶MOG2～MOG5。扫描电子显微镜(SEM)图片显示MOG2～MOG5凝胶都具有三维网络状孔隙结构。MOG2～MOG5表现出可逆的凝胶-溶胶转变,在热和机械力的作用下,MOG2～MOG5金属有机凝胶迅速转变为溶胶状态,且静置后能够恢复至凝胶状态,表现出良好的刺激响应性和自修复能力。     

[Ru(dcbpy)2dppz]2+/Fullerene Cosensitized PTB7-Th for Ultrasensitive Photoelectrochemical MicroRNA Assay

A new cosensitization photoelectrochemical (PEC) strategy was established by using a donor–acceptor-type photoactive material, poly{4,8-bis[5-(2-ethylhexyl)thiophen-2-yl]benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl-alt-3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophene-4,6-diyl} (PTB7-Th), as a signal indicator, which was cosensitized with bis(4,4′dicarboxyl-2,2′-bipyridyl)(4,5,9,14-tetraazabenzo[b]triphenylene)ruthenium(II) ([Ru(dcbpy)₂dppz]²⁺) embedded in the grooves of the DNA duplex and fullerene (nano-C₆₀) immobilized on the surface of DNA nanoflowers for microRNA assay. [Ru(dcbpy)₂dppz]²⁺ and nano-C₆₀ could effectively enhance the photoelectric conversion efficiency (PCE) of PTB7-Th as a result of well-matched energy levels among nano-C₆₀, [Ru(dcbpy)₂dppz]²⁺ and PTB7-Th, leading to a clearly enhanced photocurrent signal. Meanwhile, a target recycling magnification technique based on duplex-specific nuclease was applied in this work to obtain higher detection sensitivity. The proposed biosensor demonstrated excellent analytical properties within a linear detection range of 2.5 fm to 2.5 nm and a limit of detection down to 0.83 fm . Impressively, this cosensitization PEC strategy offers an effective and convenient avenue to significantly improve the PCE of a photoactive material, resulting in a remarkably improved photocurrent signal for ultrasensitive and highly accurate detection of various targets.     

异双席夫碱合钴(Ⅱ)配合物中性载体碘离子电极的研究

以乙二胺、乙酰丙酮缩水杨醛异双席夫碱合钴(Ⅱ)为载体的PVC膜电极,该电极对碘离子(I-)具有优良的电位响应特性并呈现反Hofmeister选择性行为,其选择性次序为I->Sal->SCN->ClO4->SO23->Br->NO2->Cl->Ac->NO3->SO42-。在pH2.0的磷酸盐缓冲体系中,对I-在1.0×10-7～1×10-1mol/L浓度范围内呈近能斯特响应;斜率为-50.7mV/dec(26℃);检出限为3.9×10-8mol/L。采用交流阻抗技术和紫外可见光谱技术研究了电极的响应机理,结果表明:配合物中心金属原子的结构以及载体本身的结构与电极的响应行为之间有非常密切的构效关系。电极具有响应快、重现性好、制备简单等优点。将电极初步应用于药物和食盐中碘的分析,结果较为满意。     

Synthesis, crystal structures, and luminescent properties of two types of lanthanide phosphonates

Hydrothermal reactions of different lanthanide(III) salts with an amino-diphosphonate ligand (H₄L=C₆H₅CH₂N(CH₂PO₃H₂)₂) led to two series of lanthanide phosphonates, namely, Ln(H₂L)(H₃L) (Ln=La, 1; Pr, 2; Nd, 3; Sm, 4; Eu, 5; Gd, 6; Tb, 7). Compounds 1-5 feature a one-dimensional (1D) chain structure in which dimers of two edge-sharing LnO₈ polyhedra are interconnected by bridging phosphonate groups, such 1D arrays are further interlinked via strong hydrogen bonds between non-coordinated phosphonate oxygen atoms into a two-dimensional (2D) layer with the phenyl groups of the ligands orientated toward the interlayer space. Compounds 6 and 7 also show a different 1D array in which the LnO₆ octahedra are bridged by phosphonate groups via corner-sharing, such chains are also further interlinked by hydrogen bonds into a 2D supramolecular layer. Compounds 5 and 7 emit red and green light with a lifetime of 2.1 and 3.7 ms, respectively.     

Co[HO2C(CH2)3NH(CH2PO3H)2]2: a new canted antiferromagnet

A new cobalt(II) carboxylate-phosphonate, namely, Co[HO2C(CH2)3NH(CH2PO3H)2]2, with a layered architecture has been synthesized by hydrothermal reactions. The Co(II) ion in the title compound is octahedrally coordinated by six phosphonate oxygen atoms from four carboxylate phosphonate ligands. Neighboring CoO6 octahedra are interconnected by phosphonate groups into a 2D layer with a 4,4-net topology. Adjacent layers are further cross-linked via hydrogen bonds between the noncoordinate carboxylate groups and noncoordinate phosphonate oxygens. The ac and dc magnetic susceptibility and magnetization measurements indicate that Co[HO2C(CH2) 3NH(CH2PO3H)2]2 is a canted antiferromagnet with T(c) = 8.75 K.     

Synthesis and insecticidal evaluation of tetrahydroimidazo[1,2-a]pyridin-5(1H)-one derivatives

A series of novel tetrahydroimidazo[1,2-a]pyridine-5(1H)-one derivatives containing a electronegative pharmacophore(=CNO₂) were synthesized via practical aza-ene reaction and characterized by ¹H NMR, ¹³C NMR, ¹⁹F NMR and HRMS. Preliminary bioassays showed that some of the target compounds exhibited good insecticidal activity against brown planthopper(Nilaparvata lugens) and cowpea aphids(Aphis craccivora) at 500 mg L^-1. Among them, compound 11h was active against brown planthopper at 100 mg L^-1. The insecticidal activities varied significantly depending on the types and patterns of the substituents, which provided guidance for further investigation on structure modifications.     

ICP-AES法测定萤石中的主次成分

萤石通过醋酸加热使ＣaＣＯ３溶解,再经过滤、沉淀、烘干,以碳酸钠、硼砂混合熔剂熔 融,酸学好以后,采用ＩＣＰ－ＡＥＳ法测定碳酸钙、氟化钙及二氧化硅、三氧化铁。此方法精密度好,回收率在９６．０％－１０１．４％之间。     

纳米金修饰玻碳电极固载抗体电位型白喉类毒素免疫传感器的研究

将巯基乙胺 (AET)固载到玻碳电极 (GCE)表面 ,进而化学吸附纳米金 (NG) ,并通过半胱氨酸 (Cys)用戊二醛 (GA)作交联剂将白喉抗体 (anti Diph)固定在玻碳电极上 ,从而制得高灵敏电位型白喉类毒素 (Diph)免疫传感器 .通过循环伏安法考察了电极表面的电化学特性 ,并对该免疫传感器的性能进行了详细的研究 .该传感器对白喉类毒素检测的线性范围是 2 4～ 60 0ng·mL-1,斜率为 3 8.9mV/decade ,线性相关系数为 0 .9979,检出限为 5 .2ng·mL-1,并将其用于生物制品中白喉类毒素的检测 ,其结果令人满意     

比较法在“仪器分析”课堂教学中的应用

相同类型的仪器之间具有紧密的联系,这些联系为“仪器分析”教学中应用比较法奠定了基础。把比较法与当前新课改要求的讨论探究模式结合起来,阐明各种仪器之间的差异和联系,有利于激发学生的学习兴趣,使学生系统、全面地掌握仪器分析知识点,从而提高教学效果。