TPPS4导数光度法同时测定茶叶中铜和锌

用pH 7.6的Na2B4O7-HCl缓冲溶液控制溶液的酸度,在OP存在下,meso-四(4-磺基苯基)卟啉与Cu2+和Zn2+在沸水浴中同时起显色反应.用Mn2+减少试剂峰对Zn2+测定的影响,其四阶导数光谱能同时测定铜和锌.Cu2+在0～0.072mg@L-1、Zn2+在0～0.096mg@L-1时遵守比耳定律,用于茶叶中铜和锌的测定,结果满意.     

悬浮体制样石墨炉原子吸收光谱法直接测定食品中的Cu、Zn、Mn

本文提出以PTFE作为化学改进剂，悬浮体制石墨炉原子吸收光谱法（GFAAS）测定食品中痕量Cu、Zn、Mn的新方法，对GFAAS测定Cu、Zn、Mn的条件进行了优化。在选定的实验条件下，测定Cu、Zn、Mn的特征捏分别为3．1pg,0.8pg和1．8pg。采用水溶液工作曲线法直接分析了食品试样中的痕量Cu、Zn、Mn，其测定结果参考值相一致，本方法无需任何化学前处理，灵敏，简便，快速。     

Raman光谱研究铜锌超氧化物歧化酶及其金属取代衍生物的二级结构

本文测定了铜锌超氧化物歧化酶（Cu2Zn2SOD)及其金属取代衍生物Cu2Ni2SOD的Raman光谱,对图谱进行了归属,并定量测定了两种SOD的二级结构,同时对结构与活性的关系进行了讨论。     

大强度阶段训练期间优秀运动员血浆和头发中必需微量元素的动态变化研究

为了研究大强度阶段训练期间优秀运动员体内必需微量元素铁、锌、铜、锰的动态变化规律 ,并探讨用无创性头发取样代替血样采集对运动员实施微量元素运动营养监控的可行性 ,以1 2名广东省优秀女子手球运动员为研究对象 ,受试者分别于夏训第 1天 ,第 7天和第 40天采取血浆 ,并同时于第 1天和第 40天采集头发 ,用原子吸收分光光度法测定头发和血浆中铁、锌、铜、锰含量。结果显示 :( 1 )夏训结束时 ,血浆Fe、Cu含量和Cu/Zn比值显著性降低 (P <0 0 5～0 0 0 1 ) ,血浆Mn显著性升高 (P <0 0 0 1 ) ,血浆Zn无差异。 ( 2 )血浆中各元素含量在整个夏训期间的变化速率不同。其中血浆Fe在夏训第 1周末即呈显著性下降 (P <0 0 0 1 ) ,显示出快速变化过程 ;而血浆Cu、血浆Cu/Zn比值的降低以及血浆Mn的升高表现为逐渐累积的缓慢变化过程 ,夏训结束才出现显著性差异 (P <0 0 5～ 0 0 0 1 )。 ( 3 )夏训结束时 ,发Fe、发Cu含量呈显著性降低 (P <0 0 5～ 0 0 0 1 ) ,但发Cu/Zn比值及发Zn含量无差异。提示 :( 1 )在大强度训练期间 ,可以考虑用发样取代血样进行微量元素铁、锌和铜的营养监控。 ( 2 )在大强度训练开始后 ,要及时对运动员进行微量元素铁和铜的补充。     

视网膜脱离后PVR的形成与氧自由基和锌、铜关系的研究

为探讨氧自由基和锌、铜在视网膜脱离后增殖性玻璃体视网膜病变 (PVR)中的作用 ,收集了 48例视网膜脱离患者视网膜下液 (SRF) ,利用紫外分光光度计测定了SRF中LPO的含量和SOD的活性 ,用原子吸收光谱法测定了Zn、Cu的含量。结果表明 ,随着PVR程度及玻璃体浑浊的加重、病程的延长 ,LPO含量增加 ,SOD活性明显下降 ,P <0 0 5 ,差异有统计学意义。提示SRF中LPO、Zn、Cu含量及SOD活性的改变与视网膜脱离后PVR的发生、发展有密切关系。     

电感耦合等离子体原子发射光谱(ICP-AES)法测定人发中铜、锌、钙、镁、铁

样品经硝酸-高氯酸消化溶解,高氯酸冒烟,盐酸溶解盐类后,在盐酸(5%)介质中,在选定的测定条件下,用电感耦合等离子体原子发射光谱(ICP-AES)法测定人发中微量元素铜、锌、铁、镁、钙。选择Cu 327.3、Zn 206.2、Fe 238.2、Mg 279.5、Ca 315.8nm分别作为铜、锌、铁、镁、钙的分析线与混合标准溶液同时测定;方法加标回收率为98.6%～101%,铜、锌、铁、镁、钙的精密度(RSD,n=8)为0.37%～2%,准确度(RE)为-3.4%～1.15%,检出限分别为0.002 3、0.001 6、0.004 6、0.003 0、0.001 4μg/mL。方法克服了分光光度法和原子吸收光谱法操作繁琐、周期长、成本高、灵敏度低等缺点。用于测定人发样品中的铜、锌、铁、镁、钙元素,测定结果与原子吸收光谱法测定值基本一致。经GBWO7061标准物质和自制标样分析验证,测定值与标准值吻合,结果准确可靠。     

稀土离子与牛血Cu(Zn)-SOD的作用

采用ESR、CD谱和荧光光谱研究了pH=6.3时六次甲基四胺-HCl缓冲溶液中LaCl_3和TbCl_3与Cu(Zn)-SOD的配位作用和结构。Cu(Zn)-SOD可增强Tb~(3+)的荧光发射,Tb~(3+)与Cu(Zn)-SOD有多个配位位置,其中有2个强结合位点,La~(3+)与Tb~(3+)可竞争Cu(Zn)…SOD上相同结合位点,77K下La~(3+)与Tb~(3+)使Cu(Zn)-SOD的Cu~(2+)活性中心的配位环境由菱形对称结构向轴对称结构转变,使Cu(Zn)-SOD的局部结构变松散,但对SOD酶活性基本无影响,表明稀土离子主要与酶蛋白分子中的酸性氨基酸羧基配位,对酶蛋白二级结构仅产生微弱扰动,对活性中心空间结构影响较小,基本不影响Cu(Zn)-SOD酶活性。     

自动加样分光光度法连续测定锌和铜

本文用自组装的自动进样分析仪研究5-Br-PADAP-OP-Zn(或Cu)体系的反应特性及适宜条件,建立了谷物、人发中锌、铜的连续测定方法。当样品中Zn/Cu的比率>4,用该方法测铜、锌互不干扰,在头发中Cu、Zn的回收率从93％～101％。     

湿法消解-原子吸收光谱法测定啤酒中痕量铅和锌

研究了用湿法消解啤酒样品、石墨炉原子吸收光谱(GFAAS)及火焰原子吸收光谱(FAAS)法分别测定啤酒中的痕量Pb2+和Zn2+。对仪器的工作参数进行了优化,探讨了混合酸消解体系、消解液用量,消解温度等因素的影响。结果表明,在200℃温度下,HNO3+HClO4(16+4)混酸能完全消解样品。Pb2+、Zn2+分别在0～80μg/L、0～1.50μg/mL范围内线性关系良好(线性相关系数r分别为0.9995和0.9997),其检出限分别为0.2μg/L、8.0μg/L。测定Pb2+、Zn2+的相对标准偏差(RSD)分别为1.8%和0.92%,加标回收率分别为96.5%和99.8%。该方法检出限低,精密度和准确度高,适用于啤酒样品中痕量铅、锌含量的测定。检测的9种啤酒样品中铅、锌含量范围分别为11.34～47.15μg/L、277～422μg/L,低于食品中的限量值。     

冷应激对铜预投大鼠血清铜锌代谢、SOD活性及GSH含量的影响

为揭示应激对体内微量元素代谢的影响和机制，预先给予大鼠不同水平的铜3周后，采用冷束缚法使大鼠产生应激，测定了血清铜、锌水平及超氧化物歧化酶(SOD)活性、还原型谷胱甘肽(GSH)和丙二醛(MDA)含量。结果表明，高铜给予没有对清洁级大鼠生长产生明显的影响．血清铜、锌及铜锌比值变化不明显，但适量的铜给予能显著提高血清中SOD活性和GSH含量；冷应激处理后大鼠血清中Cu水平下降，Zn水平升高，同时SOD消耗降低，而GSH含量显著升高。表明冷应激可使大鼠体内铜锌代谢及SOD活性和GSH含量发生变化，适量的铜给予在应激状况下才发挥出积极的生理作用。     

Cu（Ⅱ）对牛血SOD活性影响的研究

Ｃｕ（Ⅱ）对牛血ＳＯＤ活性影响的研究徐通敏，周天舒，金利通（华东师范大学化学系，上海，２０００６２）关键词超氧化物歧化酶（ＳＯＤ），铜，酶活性铜锌ＳＯＤ是广泛存在于生物体内的金属酶，其生理功能为保护生物组织免受超氧负离子和羟基的氧化损伤。牛血ＳＯＤ金...     

Zinc deficient bovine erythrocyte superoxide dismutase has low specific activity.

Zinc deficient bovine superoxide dismutase (Cu2E2SOD (E = empty)) was prepared and purified by high performance liquid chromatography (HPLC). Each peak was characterized as to protein, copper content and specific activity. The Cu2E2SOD peak fractionated by HPLC has a low specific activity at pH 7.8 (about 10% of the native enzyme (Cu2Zn2SOD)). With the addition of zinc ions, the specific activity of Cu2E2SOD was quantitatively restored to that of the native enzyme. This behavior implies that the zinc ion is very important for the appearance of enzyme activity.     

Imidazolate bridged Cu(II)-Cu(II) and Cu(II)-Zn(II) complexes of a terpyridinophane azamacrocycle: a solution and solid state study

The dinuclear Cu2+ and Zn2+ as well as the mixed Cu2+-Zn2+ complexes of a 5,5'-pentaazaterpyridinophane ligand (L) are able to incorporate imidazolate (Im-) as a bridging ligand. The crystal structure of [Cu(2)L(Im)(Br)(H2O)](CF(3)SO(3))(2).3H2O (1) shows one copper coordinated by the three pyridine nitrogens of the terpyridine unit, one nitrogen of the imidazolate bridge (Im-) and one bromide anion occupying the axial position of a distorted square pyramid. The second copper atom is coordinated by the remaining imidazolate nitrogen, the three secondary nitrogens at the centre of the polyamine bridge and one water molecule that occupies the axial position. Magnetic measurements have been performed in the 2.0-300.0 K temperature range. Experimental data could be satisfactorily reproduced by using an isotropic exchange model H = -JS(1)S(2) with J = -52.3 cm(-1) and g = 2.09. Potentiometric studies have provided details of the speciation and stability constants for the mixed Cu2+-L-HIm, Zn2+-L-HIm (HIm = imidazole) and Cu2+-Zn2+-L-HIm systems. The apparent stability constant obtained at pH = 9 for the addition of imidazole to the dinuclear Cu2+ complexes is one of the highest so far reported (log K = 7.5). UV-Vis spectroscopy and paramagnetic NMR data show that imidazole coordinates to the Cu2+ ions as a bridging imidazolate ligand from pH 5 to 10. Electrochemical reduction of the Cu2+-Zn2+-L complex occurs in two successive one-electron per copper ion quasi-reversible steps. The formal potential of the Cu2+-Zn2+-L/Cu+-Zn2+-L couple is close to that of SOD. The IC50 values measured at pH 7.8 by means of the nitro blue tetrazolium method show significant SOD activity for the dinuclear Cu2+ complexes (IC50 = 2.5 microM) and moderate activity for the Cu2+-Zn2+ mixed systems (IC50 = 30 microM).     

Determination of nonylphenol polyethoxylates in household detergents by high-performance liquid chromatography

The binding of metals to proteins in blood fractions was investigated applying hydrophobic interaction chromatography (HIC) for protein separation and graphite furnace atomic absorption spectrometry (GFAAS) as the element specific detector. For the semi-preparative separation of metalloproteins in erythrocytes and blood plasma, a HIC column (Fractogel EMD Phenyl I (S) 150 mm×10 mm I.D.) was adapted. The separation column was calibrated with the same four standard proteins as used in Pomazal et al. [Analyst 124 (1999) 657]. The sample injection volume and the ammonium sulphate gradient set-up were optimized: 20 or 200 μl, respectively, of blood plasma and of lysed erythrocytes were injected. The separated proteins were collected in 4-ml fractions and analyzed by GFAAS off-line. An optimization of the GFAAS measuring parameters for Cu, Mn, Fe, Zn, Co, Ni, and Cr was performed. For each element, a specific temperature program was optimized with respect to the matrix of the HIC eluate (0.02 M NaH₂PO₄, 1.8 M (NH₄)₂SO₄). The obtained metal profiles of the eluate were compared with the HIC chromatograms. The limits of detection (LOD) for the elements by GFAAS were: 0.5 ng Cu/ml; 0.2 ng Mn/ml; 1 ng Fe/ml; 0.2 ng Zn/ml; 0.12 ng Co/ml; 0.2 ng Ni/ml; 0.16 ng Cr/ml. The GFAAS method enabled the detection of the proteins of interest via the metals.     

Application of a Cation-Exchange Membrane to Determine Cations of Trace Metals in River Water

Donnan-membrane-equilibrium graphite-furnace atomic-absorption spectrophotometry (DME-GFAAS) has been developed to determine cations of trace metals in river water. The method employs a cation-exchange membrane to separate metal cations from their complexes; both total and cationic forms of metals were determined by means of GFAAS. The sensitivity of the method for the measurement of trace metal cations is determined by the detection limits of GFAAS for the metals of interest. Comparable concentrations of metal cations in water from NBS and from the Erhjen river were obtained between the DME-GFAAS and calculated (WATEQ4F) methods, indicating that the developed method is promising for natural fresh waters. The effect of pH on the distribution of metal cation in the NBS river water is significant for Cu and Pb; concentrations of these cations increase with decreasing pH. However, the concentrations of Cd and Zn cations do not vary with pH except that the concentration of the Zn cation decreases significantly as the pH value increases beyond 9. The method was applied to measure the capacity of complexing Cu in Chung-Lu river water, which was estimated to be 2.3 μM.     

A study on the mimics of Cu-Zn superoxide dismutase with high activity and stability: two copper(II) complexes of 1,4,7-triazacyclononane with benzimidazole groups

Two copper(II) complexes [CuL(1)Cl]ClO(4) and [CuL(2)MeCN](ClO(4))(2)xH(2)O were synthesized (L(1)= 1-(benzimidazole-2-ylmethyl)-1,4,7-triazacyclononane, L(2)= 1,4-bis(benzimidazole-2-ylmethyl)-1,4,7-triazacyclonone). The benzimidazole groups were N-substituents of tacn, and the complexes are more stable than their parents. They are able to catalyse the dismutation of superoxide anion in aqueous solutions at physiological pH and in bovine serum albumin solution (0.5 mg ml(-1)). X-ray structure analysis and EPR and electronic spectra show that the structure of complex is more similar to the Cu(II) centre of Cu(2)Zn(2)SOD than that. Comparing with other Cu(II) complexes, the complex possesses both high SOD activity and highly thermodynamic stability.     

外源铜增强天然铜锌超氧化物歧化酶断裂DNA的活性

铜锌超氧化物歧化酶（CuZnSOD）作为一种抗氧化酶, 最重要的功能是催化超氧阴离子歧化为过氧化氢和氧气。然而最近研究发现CuZnSOD具有过氧化物酶活性,能导致核酸、蛋白质和细胞膜的损伤。本工作采用光谱学和酶学方法研究外源Cu(Ⅱ)与CuZnSOD之间的相互作用,以及H₂O₂存在下外源Cu(Ⅱ)对 CuZnSOD断裂DNA活性的增强效应。比较CuZnSOD + nCu(Ⅱ) (n=0, 1, 2, 4, 6, 8)和单独Cu(Ⅱ)分别断裂DNA的活性,表明外源Cu(Ⅱ)的加入可显著增强CuZnSOD断裂DNA的活性。相对酶活力和稳态动力学的测定证实了这种增强效应。pH依赖性实验表明断裂DNA的最适pH范围为pH3.6-5.6和pH9.0-10,在不同的pH区域CuZnSOD + nCu(Ⅱ)断裂DNA途径可能不同。     

二价金属离子激活铜超氧化物歧化酶断裂DNA的活性

以铜超氧化物歧化酶(CunSOD, n＝1—4)作为野生型CuZnSOD突变体的一种模型, 研究了其在二价金属离子(Mg2+, Mn2+)存在下由非氧化途径断裂DNA的活性, 并与CuZnSOD和脱辅基SOD(apoSOD)进行了比较. 结果表明, 在Mg2+或Mn2+存在下, CunSOD断裂DNA的活性高于CuZnSOD和apoSOD, 并且DNA的断裂活性受二价金属离子浓度、pH及酶浓度等因素影响. 相对活性及动力学参数的测定结果表明, CunSOD断裂DNA的相对能力按Cu1SOD2SOD≈Cu4SOD3SOD的顺序变化.     

ESR and photoluminescence properties of Cu doped ZnS nanoparticles

Nanoparticles of Zn1-xCuxS with Cu concentrations of x=0.0, 0.1, 0.2, 0.3 and 0.4 were prepared by a co-precipitation reaction method from homogeneous solutions of zinc and copper salts. Both the ZnS and ZnS:Cu nanoparticles excited at about 370 nm exhibits a broad green emission band peaking around 491 nm, which confirms the characteristic feature of Zn2+ as well as Cu2+ ions as luminescent centers in the lattice. The TEM micrographs showed spherical morphology for ZnS nanocrystals and the average size of the particles was estimated to be around 8.5 nm. At liquid nitrogen temperature, ESR signal characteristic of Cu2+ ions was observed in samples of all concentrations. ESR spectra analysis also indicated that Cu2+ ions enter the host lattice by replacing Zn2+ ions with distorted tetrahedral site symmetry.