Macrocyclic compound as ionophores in lead(Ⅱ) ion-selective electrodes with excellent response characteristics

Macrocyclic compounds,such as crown ethers,azacrown ethers,thiacrown ethers,calixarenes and porphyrins,which act as ionophores in lead(Ⅱ) ion-selective electrodes,are systematically summarized based on the latest literatures.The molecular structure characteristics of the ionophores are general-ized.The modification regulations for the substituted ionophores are elaborated with the purpose of improving the response features of the lead(Ⅱ) ion-selective electrodes assembled by them.It is pointed out that the introduction of pendant moieties which contain soft base coordination centers like N,S and P atoms is in favor of adjusting the cavity size and conformation of the macrocyclic com-pounds.Furthermore,there is synergic effect between the cavity and the donor sites of the ligand and thus the selective complexation of lead ions is easily realized,resulting in significant avoidance of the interference from other metal ions.The macrocyclic ionophore having the best response characteris-tics thus far was found to be N,N'-dimethylcyanodiaza-18-crown-6 with the detection limit of 7.0×10-8(14.5 μg/L),which is one of the uncommon ionophores that can really eliminate the interference from silver and mercury ions.The selectivity coefficients of the ionophore for lead ions over other metal ions,such as alkali,alkaline earth and transition metal ions are in the order of 10-4 or smaller,where the se-lectivity coefficient of lead(Ⅱ) over mercury(Ⅱ) ions is much lower,down to 8.9×10-4.The structure de-sign idea for high-performance ionophore is proposed according to present results.The incorporation of nitrogen atom,especially cyano group or thiocyano group or amino/imino groups,rather than thio atom alone could result in new excellent lead ionophores.The aborative design for metacyclophanes containing aromatic nitrogen atoms with the aim of creating excellent ionophores would also become a potential research trend.The lead(Ⅱ) ion-selective electrodes have shown widely potential applications in the potentiometric titration,and flow injection potentiometry,and in the direct determination of lead in stack emissions of lead smelters,and assay of lead in rocks,particularly in the direct measurements of trace amount of lead(Ⅱ) in human hair,blood,edible oil,food,water,and air.     

Effects of sulfide on sulfate reducing bacteria in response to Cu（Ⅱ）, Hg（Ⅱ） and Cr（VI） toxicity

Sulfate reducing bacteria (SRB) is identified as the primary organisms responsible for the treatment of heavy metal wastewater. However, most heavy metals can inhibit the growth of SRB during heavy metal treatment processes. Sulfide is a metabolic product of SRB and it can precipitate or reduce heavy metals. This study focused on the effects of sulfide on SRB resistance to Cu(II), Hg(I) and Cr(VI) toxicity. First, we considered the existence style of various heavy metals with and without sulfide addition by...     

具生物功能的二氧四胺大环金属配合物的研究 Ⅱ．Cu（Ⅱ），Ni（Ⅱ）配合物的电化学研究

用循环伏安法研究了四个ｎｐｄｔ和ｄｔ的铜（Ⅱ）和镍（Ⅱ）配合物在水溶液中的氧化还原过程，讨论了ｐＨ值对ｎｐｄｔ的铜（Ⅱ）、镍（Ⅱ）配合物的ＣＶ曲线的影响，并测定了两种铜（Ⅱ）配合物在电极表面的异相电子转移反应速率常数，二者的速率常数相近。     

新型四氮杂大环镍（Ⅱ）配合物的合成、表征和电子光谱研究

在水溶液中合成了新型四氮杂大环Ｈ４Ｌ（５，１２－二苯基－７，１４－二甲基－１，４，８，１１－四氮杂环十四烷－Ｎ′，Ｎ″，Ｎ，Ｎ＂＂－四乙酸）与镍（Ⅱ）形成的固体配合物，采用元素分析、ＩＲ等技术表征出配合物的组成为ＮｉＨ２Ｌ·２Ｈ２Ｏ，由电子光谱数据探讨了配合物的成键特征     

Correlation of mechanical properties in bulk metallic glasses with ~（27）Al NMR characteristics

We report 27Al NMR and magnetic susceptibility measurements of Zr and ZrHf-based bulk metallic glasses (BMGs). 27Al NMR Knight shift shows that there exists a clear correlation between the local electronic properties at Al sites and mechanical properties. In addition,magnetic susceptibility measurements also provide clues on the influence of the electronic states,especially the strong influence of d-orbital characteristics on the mechanical properties of toughness and hardness.     

十三员四氮杂大环镍（Ⅱ）配合物参与的新型振荡化学反应

本文报道了［ＮｉＨＡＴ］２＋配合物催化ＮａＢｒＯ３氧化芳香有机底物没食子酸而产生的新型振荡化学反应。描述了该体系的振荡特性。研究了各物种初始浓度以及自由基抑制剂等对振荡的影响。     

十四员四氮杂大环铜（Ⅱ）配合物参与的新型振荡化学反应

本文报道了一种新型振荡化学反应体系：ＮａＢｒＯ~３－ＣＨ~２（ＣＯＯＨ）~２－Ｈ~３ＰＯ~４ＣＵＬ（２＋）（Ｌ为５，７，７，１２，１４，１４一六甲基一１，４，８，１１一四氮杂环十四一４，１１一二烯）．研究了体系中各物种的初始浓度、温度、还原性物质（维生素Ｃ和草酸）、自由基抑制剂（丙烯腈、丙烯酰胺、Ｈ~２Ｏ~２）、Ａｇ＋、Ｈｇ（２＋）、Ｌ一半胱胺酸等因素对振荡的影响。     

24元环双核铜（Ⅱ）配合物的合成及其对超氧化物歧化酶的模拟──Ⅲ．配合物的电化学研究

由２，６－二乙酰基吡啶与３－氧杂戊烷１，５－二胺缩合成大环配体，首次用循环伏安法研究了在水溶液中它与铜（Ⅱ）生成以Ｈ２Ｏ，ｉｍ－，Ｎ－３和ＳＣＮ－为桥联的双核配合物的氧化还原过程，探讨了两中心原子间的作用，联系配合物歧化活性提供的信息，从电化学角度解释了活性实验的结果。     

卤化银选择电极对干扰离子的动力学响应

用活度阶梯法研究了ＡｇＩ和 ＡｇＢｒ电极对干扰离子的瞬时响应信号。对于非单一瞬时信号,所测定的平衡电位选择性系数符合相应化合物的溶度积比值,证实瞬时信号产生的机理是离子交换反应。离子交换产物的溶度积越小,离子水合焓差越小,瞬时信号负峰高度越大,水合焓差还可以解释正负峰高度比,这些都证明瞬时信号峰电位是决定于离子交换速度而不是离子扩散速度。瞬时信号是非单一型还是单一型决定于平衡时离子交换产物的摩尔分数和干扰离子浓度,也与两离子的水合焓差有关。     

Measurement of trace lead (II) in water samples with biomacromolecule heparin modified electrode

A new method for electrode modification and accumulation with a biomacromolecule and subsequent voltammetric quantittion of metal ions is described. Heparin is used as the surface modifier, and the method is based on formation of the heparin complex of lead (II). The voltammetric responses were evaluated with respect to electrolyte, pH, preconcentration time, and lead concentration. The electrode composition, voltammetric wave form and other variables have also been taken into account. A detection limit of 3.0×10⁻⁹ mol/L has been obtained by preconcentration for 20 min. The method is sensitive, simple and relatively rapid, with a relative standard deviation of 5.2% at the 1.0×10⁻⁷ mol/L level. Supported by the Trants-Century Training Program Foundation for the Talents from the State Commission of Education of China: the national Natural Science Foundation of China and the Opening Laboratory Foundation of Changchun Institute of Applied Chemistry, Chinese Academy of Sciences. Li Huiling: Born in July 14, 1972. Master of Science.     

硅藻土对铅离子的静态吸附实验研究

研究了硅藻土在不同pH值、温度、吸附时间、铅离子初始浓度、硅藻土用量等条件下对吸附铅离子的影响,并以铅离子的去除率为实验指标,进行单因素实验、正交实验。结果表明:在吸附温度为25℃、pH=1.0、硅藻土溶液用量为3.0 g/25 mL、硅藻土溶液起始浓度为30 mg/L时,去除率最高。     

以1,2-双(3-氨基苯氧基)乙烷为载体的PVC膜银离子选择电极的研究

制备了以1,2-双(3-氨基苯氧基)乙烷为载体的聚氯乙烯(PVC)膜银离子选择电极,研究了电极膜中增塑剂种类及载体和离子定域体(KTpCIPB)含量对电极性能的影响.结果表明:此电极对Ag+具有很好的能斯特响应性能,在10(-6)～10(-3) mol/L的浓度范围内呈良好的线性关系,线性系数为0.9991,检测下限为8.5X10(-7)mol/L,响应斜率为59.9 mV/decade.电极对Ag+具有很好的选择性,碱金属、碱土金属及常见过渡金属离子对Ag+的测定干扰很小.该电极可在体积分数不大于30%的乙醇水溶液中使用,能准确滴定自来水中C1-的含量和维生素B6药片中维生素B6的含量,并用于实际样品中Ag+含量的直接测定.     

以双(N-甲基-N-苯基氨基二硫代甲酸)1,4-丁二醇酯为载体的PVC膜银离子选择电极的研究

报道了以双(N-甲基-N-苯基氨基二硫代甲酸)1,4-丁二醇酯为载体的PVC膜电极的响应行为.结果表明:该选择电极对银离子有良好的灵敏度和高选择性,在10-3~10-6mol/L的浓度范围内响应斜率为53.3 mV/paAg ,检测下限为3.8×10-7mol/L,碱金属、碱土金属及过渡金属离子不干扰银的测定,电极具有较好的重现性和稳定性.该电极可作为Ag 准确滴定卤素阴离子和维生素B1药片中维生素B1含量的电位滴定指示电极,并用于水样中银离子含量的直接测定.     

四氮杂大环铜(II)配合物催化羧酸酯水解研究

合成并表征了一种四氮杂大环配体及其铜(II)配合物.在Brij35胶束溶液中,试验了该配合物对羧酸酯(2-吡啶甲酸对硝基苯酚酯PNPP)水解的催化活性,研究了其催化PNPP水解的动力学,提出了可能的催化反应的机理.     

新型PVC膜银离子选择电极的研制及应用

以合成的双(N-乙基-N-苯基氨基二硫代甲酸)1,3-丙二醇酯为载体,采用双层膜电位法直接测定了溶剂聚合物膜中载体与金属离子的络合物生成常数.制备并考察了以双(N-乙基-N-苯基氨基二硫代甲酸)1,3-丙二醇酯为载体的银离子选择电极的性能.实验结果表明:该选择电极对银离子有良好的响应性能和高选择性,在10-3~10-6mol/L的浓度范围内响应斜率为56.0 mV/paAg+,检测下限为3.7×10-7mol/L,碱金属、碱土金属及过渡金属离子不干扰银的测定.该电极可作为测定维生素B1药片中维生素B1含量的电位滴定指示电极和水样中银离子含量的直接测定.     

Electrochemical determination of trace amounts of lead (II) and cadmium (II) at a calix[6]arene modified carbon paste electrode

An electrochemical method for the simultaneous determination of lead(II) and Cadmium(II) with a calix[6]arene modified carbon paste electrode (CPE) has been developed. Pb²⁺ and Cd²⁺ were accumulated at the surface of the modified electrode via formation of chemical complexes with calix[6]arene, and reduced at 1.40 V. During the following anodic potential sweep, reduced lead and cadmium were oxidized, and two well-defined striping peaks appeared at about −0.60 V and −0.84 V. Compared with a bare carbon paste electrode, the calix[6]arene modified CPE greatly improves the sensitivity of determining lead and cadmium. The stripping peak currents change linearly with the concentration of Pb²⁺ 3.0×10⁻⁸–8.0×10⁻⁶ mol·L⁻¹ and with that of Cd²⁺ 6.0×10⁻⁸–1.0×10⁻⁵ mol ·L⁻¹. The detection limits of Pb²⁺ and Cd²⁺ are found to be 8.0×10⁻⁹ mol·L⁻¹ and 2.0×10⁻⁸ mol·L⁻¹, respectively. The modified carbon paste electrode was applied to determine trace levels of lead and cadmium in water samples. Comparing with that of atomic absorption spectrometry, the results suggests that the calix[6]arene modified CPE has great potential for the practical sample analysis. Foundation item: Supported by the National Natural Science Foundation of China (60171023) Biography: JI Xiao-bo (1980-), male, Master, research direction: electroanalytical chemistry.     

以水杨醛缩邻氨基苯甲酸合铜为中性载体的硫氰酸根PVC膜电极

以水杨醛缩邻氨基苯甲酸合铜(II)[CuI(I)-HBAB]为中性载体,制备了一种对硫氰酸根(SCN-)具有优良的电位响应特性并呈现出反Hofmeister选择性行为的离子电极,其选择性次序为:SCN->ClO4->Sal->I->SO 32->NO3->Br->Cl->SO42-。该电极在pH=5.0的磷酸盐缓冲体系中具有最佳的电位响应,在1.0×10-6～1.0×10-1m ol/LSCN-浓度范围呈近能斯特响应,斜率为-57.5mV/dec(25℃),检测下限为5.0×10-7mol/L。采用交流阻抗和紫外光谱分析技术研究了配合物中心金属原子以及配合物本身的结构对电极电位响应行为的作用机理。将该电极用于废水分析,结果令人满意。