痕量铜的合并带法流动注射分析——Fe~(3+)-S_2 O_3~(2-)-Cu~(2+)催化体系

本文基于 Cu~(2+)对三价铁离子与硫代硫酸盐反应生成深紫蓝色物质的褪色反应的催化作用采用流动注射合并带技术,建立了痕量铜(Ⅱ)的快速分析方法。方法的线性范围在0～350μg/L 检出限为10μg/L,相对标准偏差为1.68％,进样频率可达100样次/小时,具有很高的选择性。     

铜、钴、镍同时分离工艺的研究

稀土体系三种元素同时分离的工艺最近已有发表,但非稀土方面的工作尚未见报导.对Cu、Co、Ni三种元素,通常是将Cu、Co作为一个组份与Ni分离.本工作对组成为Cu:Co:Ni=1:1:1的水相合成料液设计了两种工艺,进行了串级实验,实现了该三种元素的同时分离, 串级实验以HEH(EHP)作萃取剂,煤油为稀释剂,其它试剂均用分析纯.     

Solubility and Ionic Processes in the Cu X 2? MX ?H2O ( X ?=Cl?, Br?; M +=Li+, Na+, K+, NH4+, Cs+) Systems

Summary.  Solubility isotherms in the CuBr₂−MBr−H₂O (M ⁺ = Li⁺, Na⁺, Cs⁺) systems at 298.15 K were measured. The results together with other available literature data for copper chloride and bromide systems were treated by hydration analysis, and comparative discussion of ionic processes taking place in the respective saturated solutions was performed. Corresponding author. E-mail: jitka@prfdec.natur.cuni.cz Received August 6, 2002; accepted (revised) November 29, 2002 Published online April 3, 2003     

Potentiometric studies on the complexation of copper(II) by phenolic acids as discrete ligand models of humic substances

Studies on the complexation of copper(II) by phenolic acids, as ligand models of humic substances were done by potentiometry. The acids under study were: 3,4-dihydroxyhydrocinnamic acid or hydrocaffeic acid (1), 3,4-dihydroxyphenylacetic acid (2) and 3,4-dihydroxybenzoic acid or protocatechuic acid (3). Acidity constants of the ligands and the formation constants of metal-ligand complexes were evaluated by computer programs. The carboxylic group of the phenolic acids has different pK_a1 values, being the dissociation constants intrinsically related with the distance between the function and the aromatic nucleus. The results obtained allow concluding that acidity constants of the catechol moiety of the compounds are similar with pK_a2 and pK_a3 values between 9.47-9.41 and 11.55-11.70. The complexation properties of the three ligands towards copper(II) ion are quite similar, being the species found not different either in nature or stability. Although the model ligands have some structural differences no significant differences were found in their complexation properties towards copper(II). So, it can be postulated that complexation process is intrinsically related with the presence of a catechol group.     

Ein neues Kupfercobaltboratoxid mit isolierten B2O5-Baugruppen: Cu2Co(B2O5)O

On a New Copper Cobalt Borate Oxide with Isolated B₂O₅ Units: Cu₂Co(B₂O₅)O Single crystals of a new compound with the empirical formula Cu₂CoB₂O₆ were obtained by using a B₂O₃ flux technique. X-ray single crystal technique led to a new structure type. Cu₂CoB₂O₆ crystallizes monoclinic, space group C-P2₁/c (No. 14); a = 3.2250(6); b = 14.847(1); c = 9.1171(6) Å; β = 93.67°; Z = 4. All metal sites are octahedrally coordinated and form a two dimensional framework consisting of edge sharing octahedra ribbons. In addition one observes isolated B₂O₅-units and oxygen which is not coordinated to boron. The far relation to the crystal structure of the mineral Warwickite is illustrated.     

Ferromagnetically coupled heterobinuclear Cu(Ⅱ)-Ln(Ⅲ) complexes with N,N''''-bis(2-aminoethyl)-oxamido dianion as a bridged ligand

Six novel μ-oxamido heterobinuclear complexes, namely Cu(oxae)Ln(Me2bpy)2-(ClO4)3 (Ln=La, Nd, Gd, Tb, Ho, Er), where oxae denotes N, N'-bis(2-aminoethyl)oxamido dian-ion, Me2bpy is 4,4'-dimethyl-2,2'-bipyridyl, have been synthesized and characterized by elemental analyses, IR, conductivity measurements and electronic spectra. The temperature dependence of the magnetic susceptibility of Cu(oxae)Gd(Me2bpy)2(ClO4)3 has been meaured over the range 4-300 K. The least-squares fit of the experimental susceptibilities yielded J - 1.87 cm-1.The observed Gd(Ⅲ)-Cu(Ⅱ) coupling is ferromagnetic. One plausible mechanism that can cause a ferromagnetic coupling between Gd(Ⅲ) and Cu(Ⅱ) is discussed in terms of spin-polarization.     

LSGMC5含量对于二甲醚燃料电池复合Ni-Fe阳极性能的影响

用浸渍法制备了掺杂不同质量分数的La0.8Sr0.2Ga0.8Mg0.15Co0.05O3-δ (LSGMC5)粉末的Ni8-Fe2-LSGMC5复合阳极, 并采用交流阻抗和直流极化技术考察了以氢气和二甲醚为燃气时该复合阳极的电化学性能及相应电池的功率输出特性. 结果表明, 在电极中掺入LSGMC5 粉末, 能显著地改善电极的形貌和电极/电解质界面结构, 减小欧姆电阻和极化电阻. 电极中LSGMC5 粉末含量对于氢气及二甲醚电化学氧化性能的影响显著不同. 以二甲醚为燃气时, 电极极化电阻随LSGMC5 粉末含量的增加而减小, 其中LSGMC5 掺杂量为30%的复合阳极具有最高的电化学性能, 相应电池在1073、1023、973 K 时的输出功率分别为1.00、0.61、0.40 W·cm-2; 以氢气为燃气时, LSGMC5 掺杂量为20%的复合阳极具有最好的电化学性能, 随着LSGMC5 掺杂量的进一步增加, 电极极化电阻显著增大.     

1-(2,6-二氯-4-硝基苯)-3-(4-硝基苯)-三氮烯与铜的显色反应研究及其应用

研究了新试剂1-(2,6-二氯-4-硝基苯)-3-(4-硝基苯)-三氮烯(DCNPNPT)与铜(Ⅱ)显色反应。在表面活性剂Tween-80存在下,pH 9.0～10.0范围内,铜(Ⅱ)与DCNPNPT形成1:4黄色配合物,其最大吸收波长为460nm,用双峰双波长法测定,表观摩尔吸光系数为1.I×10~5L·mol~(-1)·cm~(-1)。铜(Ⅱ)含量在0～240μg·L~(-1)范围内符合比耳定律。拟定方法用于铜矿和环境水标样中铜的测定,结果满意。     

亚临床肝性脑病患者的血清锌,铜含量的测定及临床意义

检测了３０例慢性活动性肝炎患者、３０例肝硬化患者、３０例亚临床肝性脑病患者血清中的铜、锌含量，并与正常对照组进行比较分析，探讨了微量元素铜、锌的血清含量改变及其影响因素，分析其临床意义。结果表明体内的铜锌含量与肝脏功能有密切的关系。在慢性活动性肝炎时，虽然肝脏功能有一定的损害，但由于肝脏的代偿能力强，铜，锌含量仍可保持在正常水平，而在肝硬化、亚临床肝性脑病时，铜锌明显降低，而铜锌含量的降低又导致机     

内蒙古牧区蒙、汉族人发铜、锌、铁、锶及钙的X-射线荧光光谱法测定

用X-射线荧光光谱法，测定了387例内蒙古牧区蒙古族、汉族成人和儿童的发中铜(Cu)、锌(Zn)、铁(Fe)、锶(St)及钙(Ca)的含量，对同一地区蒙、汉族成人间，成人及儿童间发中五种元素含量进行了比较分析。结果表明：蒙汉族成人发中Cu，Zn、Fe含量不受种族及饮食习惯的影响，其含量无显著性差异；蒙汉族成人发中Sr和Ca含量存在着相平行的显著差异；牧区儿童发Zn含量与牧区成人发Zn含量差异无显著性意义，提示牧区儿童不缺Zn，可能与多动物性食物有关；牧区儿童发中Cu、Fe、Sr、Ca均显著低于牧区成人、可能与儿童发育旺盛和Zn摄入量高对Cu、Fe吸收发生抑制有关。