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1.
研究了丁二酮肟 氨 氯化铵 柠檬酸钠 明胶 抗坏血酸体系中Cu(Ⅱ )、Pb(Ⅱ )、Cd(Ⅱ )、Ni(Ⅱ )和Co(Ⅱ )的络合物吸附波 ,建立了同时测定水溶液中痕量相应元素的新方法。上述金属络合物分别在 -0 .44、-0 60、-0 .76、-1.0 7和 -1.2 4V左右产生灵敏的极谱波。信噪比为 3时 ,检出限分别为 1.0× 10 - 8、2 .3×10 - 8、1.3× 10 - 8、2 .9× 10 - 1 0 和 3 .6× 10 - 1 1 mol/L。铜、铅、镉、镍和钴的浓度分别为 2 .0× 10 - 8~ 2 .0× 10 - 5,4.8× 10 - 8~ 4.8× 10 - 5,3 .0× 10 - 8~ 3 .0× 10 - 5,5 .4× 10 - 1 0 ~ 5 .4× 10 - 7和 6.8× 10 - 1 1 ~ 6.8× 10 - 8mol/L时 ,与相应峰电流线性关系良好。方法用于同时快速测定实际样品中这些金属离子 ,获得满意结果  相似文献   

2.
脱硫脱硝一体化催化剂SnO2-TiO2的程序升温还原及脱附研究   总被引:2,自引:0,他引:2  
对以CO为还原剂同时还原SO2,NO为S和N2的反应。SnO2和TiO2(锐钛矿)没有催化活性。但它们组合成固溶体后,显示出很高的活性,说明它们之间存在协同效应.我们采用CO—TPR和NO—TPD证实SnO2和TiO2之间的协同效应表现为几何效应即TiO2使SnO2良好分散在TiO2的内孔表面和电子效应即TiO2促进SnO2表面晶格氧的还原和削弱NO的吸附能力.CO—TPR研究证明SnO2或SnO2-TiO2中被CO还原的晶格氧数只是总晶格氧数的10^-5,说明这部分晶格氧为表面晶格氧。这是在CO存在下SnO2或SnO2-TiO具有催化氧化还原活性的前提.  相似文献   

3.
研究了一种快速、简便测定大鼠心肌组织中次黄嘌呤(HX)、肌苷(I)和腺苷(ADO)的高效液相色谱法。采用WatersμBondapakC_(18)色谱柱,含7%甲醇的2mmol/L磷酸钠缓冲液(pH=6.0)为流动相,等比洗脱,254nm处紫外检测,12min内即可分析一个样品。本法生物样本预处理简单,因而平均回收率达95%以上。HX在5.0~500ng,I和ADO在10~1000ng范围内,线性关系良好,相对标准偏差分别低于3.40%(日内)和5.20%(日间),并测定了30份心肌组织中次黄嘌呤、肌苷和腺苷的含量。对所用的色谱分析条件进行了讨论。  相似文献   

4.
分子磁体化合物的设计合成是近年来迅速发展的一个新兴前沿领域[1 ,2 ] ,它涉及化学、物理、材料等诸多领域 ,多核配合物体系是分子磁体化合物中研究最为广泛和深入的一类体系。在多核金属配合物中 ,异多核体系的分子磁性研究尤为引人注目。有关草胺酸类、草酰胺类、草酸根类、二肟类和氰根类多原子桥异多核配合物分子磁体的设计合成已有综述报道[3] 。硫氰酸根可以将多个顺磁性金属离子桥联成一维、二维或三维分子 ,但有关硫氰酸根桥异多核配合物磁性研究的报道比较少[4,5] ,本文报道二个硫氰酸根桥联异三核配合物的合成与磁性研究。1 实…  相似文献   

5.
介绍了硒代胱氨酸修饰银电极的制备及其电化学特性 ,并将该修饰电极用于痕量金属离子的分析。研究结果表明 ,此修饰电极具有良好的电化学性质和化学、机械和电化学的稳定性 ,在测定Pb2 + 时 ,检出限可达到 1.0× 10 - 11mol·L- 1,线性范围在 2 .0× 10 - 10 ~ 4 .0× 10 - 11mol·L- 1,同时对于其他金属离子 (Cd2 + ,Cu2 + ,Zn2 + )的分析中也获得较满意的结果  相似文献   

6.
各种文件书写材料的种类、形成时间的鉴定研究是司法活动中十分关注的课题,曾建立了许多鉴定方法,如气相色谱法、高效液相色谱法、傅里叶红外光谱法等。  相似文献   

7.
The reaction of 5-sulfosalicylic acid(H3-SSA) with o-phenanthroline(Phen),NaOH,and Mcl2(M=Zn,Cu) affords Zn(H-SSA)(Phen)(H2O)2(1) and Cu(H-SSA)(Phen)(H2O)2 (2),respectively ,compounds 1 and 2 are characterized by elemental analysis,IR,fluorescence spectra and single crystal Xray diffraction analysis.The X-ray diffraction analyses reveal that compounds 1 and 2 are isostructure.The 5-sulfosalicylic acid ligand loses two protons at the sulfo-group and carboxylic group during the reaction.The Zn(II) and Cu(II)ions are sixcoordinated and adopt distorted octahedral geometry,which are surrounded by two N atoms from Phen,two O atoms from two water molecules,one O atom from-SO3 group and one oxygen from carboxylic group of the other H-SSA.Compounds 1 and 2 have unprecedented one-dimensional linear chain formed by a repeating mononuclear structureal unit.which is bridged by H-SSA.The fluorescence intensity of 1 and 2 is stronger than that of Phen and H3-SSA at 400nm.The lowest excited single states of these complexes are assigned as mainly Phen localized 1(π π),The antibacterial activity test shows that compounds 1 and 2 strongly inhibit the growth of Streptococcus haemolyticus,Straphylococcus aureus and Escherichia coli.  相似文献   

8.
焉翠蔚  李延团等 《应用化学》2001,18(10):806-809
以N,N'-双(3-氨基-2,2-二甲基丙基)草酰胺根阴离子(Me2oxpn)为桥联配体,分别端接N,N,N',N'-四甲基乙二胺(tmen)和2,9-二甲基-1,10-邻菲甲啉(Me2-phen);合成和表征了3种新的异双核配合和物[Cu(Me2oxpn)Fe(tmen)2]SO4(a),[Cu(Me2oxpn)Zn(tmen)2]SO4(b)和[Cu(Me2oxpn)Zn(Me2-phen)2]SO4(c)。经元素分析、红外光谱、电子光谱、电导及磁性测量等方法推定了这些配合物的结构。测定并研究了(a)的变温磁化率(4-300K),求得交换参数J=-12.96cm^-1,表明双核配合物中Cu(Ⅱ)-Fe(Ⅱ)离子间存在反铁磁超交换作用。测试了3个双核配合物的杀菌作用。  相似文献   

9.
固相萃取-高效液相色谱法测定动物尿样中的莱克多巴胺   总被引:10,自引:0,他引:10  
应永飞  皮雄娥  陈慧华  朱聪英 《色谱》2006,24(3):320-320
莱克多巴胺(ractopamine)是一种新型的β-肾上腺素兴奋剂,我国农业部、卫生部、国家药品监督管理局在2002年联合下发的176号公告中已经明确将其列入禁用药品名单。目前,文献报道的莱克多巴胺的检测方法很少,特别是国内还未见文献报道。由于莱克多巴胺在动物体内代谢较快,因而药物往往以原形的形式从体内排出。检测动物尿样具有快速、准确等特点,建立动物尿样中的莱克多巴胺的检测方法可以对畜产品生产过程中使用莱克多巴胺的现象进行有效的监控。因此,探索动物尿样中莱克多巴胺的检测方法具有非常重要的理论意义和实际价值。本文建立了动物尿样中莱克多巴胺残留量的高效液相色谱(HPLC)测定方法,样品处理简单,灵敏度高。  相似文献   

10.
烟草中的甾醇类物质主要有胆甾醇、菜油甾醇、豆甾醇和β-谷甾醇等,这些甾醇的结构中都含有羟基(结构式见图1),热解时其母体的多环结构可形成稠环芳烃,因此烟草中的甾醇是一种潜在的影响人体健康的物质,故对甾醇种类和含量进行分析对卷烟的配方研究具有参考价值。  相似文献   

11.
本文介绍了一种利用荧光熄灭定量的测定铜(II)的新方法。从新鲜菠菜中提取叶绿素-a,用高氯酸溶液处理,制得脱镁叶绿素-a。测量脱镁叶绿素-a的紫外-可见吸收光谱,观测到505和535nm处有特征吸收峰。在60 ℃水浴中,脱镁叶绿素-a的丙酮溶液与铜(II)离子水溶液混合,5分钟后发现混合液颜色变绿,505和535 nm处吸收峰消失。铜(II)离子水溶液与脱镁叶绿素-a的丙酮溶液混合后发生荧光猝灭现象,而类似浓度的其它生理离子在相同反应条件下对脱镁叶绿素-a的荧光猝灭现象不明显。 研究了铜(II)离子与脱镁叶绿素-a的反应时间,反应温度对荧光强度衰减的影响。并通过阿累尼乌斯经验关系估算铜(II)离子与脱镁叶绿素-a反应的活化能约为10 ±1kJ·mol-1。研究了铜(II)离子的浓度对脱镁叶绿素-a的丙酮溶液荧光强度的影响,在8.0×10-5 ~8.0×10-7 mol·dm-3范围内,铜(II)离子的浓度与混合液的荧光强度成线性衰减关系,检测限可达8.0×10-7 mol·dm-3。利用脱镁叶绿素-a的丙酮溶液的荧光强度变化测量,有望发展成为一种检测铜(II)离子的新方法。  相似文献   

12.
《Electroanalysis》2005,17(24):2260-2265
A new Cu(II) ion‐selective PVC membrane sensor based on 6‐methyl‐4‐(1‐phenylmethylidene)amino‐3‐thioxo‐1,2,4‐triazin‐5‐one (MATTO) as an excellent sensing material was developed. The electrode exhibits a Nernstian slope of 29.2±0.4 mV per decade over a very wide concentration range between 1.0×10?1 and 1.0×10?6 M, with a detection limit of 4.8×10?7 M (30.5 ng/mL). The sensor possesses the advantages of short conditioning time, fast response time (<10 s), and especially, very good selectivity towards transition and heavy metal, and some mono, di and trivalent cations. The proposed electrode was successfully applied to the determination of copper in wastewater of copper electroplating samples and as an indicator electrode in potentiometric titration of Cu(II) ions with EDTA.  相似文献   

13.
《Electroanalysis》2004,16(24):2065-2072
The interaction between Cu(II) and pectin extracted from citrus fruit was studied in KNO3 0.10 mol dm?3 at 25 °C and pH 5.5, using ion selective electrode potentiometry and voltammetry, namely differential pulse polarography and square‐wave voltammetry. Although many independent variables may affect Cu(II)‐polymer interactions such as charge density, polymer concentration and copper to polymer concentration ratio, a good fitting was observed for the model with ML and ML2 complex species, when M:L total concentration (mol dm?3) ratio varies from 0.2 to 2.7 and the ligand concentration is in the range (0.2 to 1) g dm?3, i.e., (0.4 to 2)×10?3 mol COO? dm?3. The complex parameters found in these conditions were log βCuL=3.5±0.1 and log βCuL2= 8.0±0.2. For lower total ligand and total metal ion concentrations, used in voltammetry, the interaction Cu(II)‐pectin is affected by a cooperative mode (increase of metal ion‐ligand affinity) when the total metal ion concentration increases and by an anti‐cooperative mode when the total ligand concentration increases, possibly due to different conformations of the polymer.  相似文献   

14.
许文菊  袁若  柴雅琴 《中国化学》2009,27(1):99-104
本文以2,9,16,23-四硝基酞菁铜(II) (Cu(II)TNPc) 和2,9,16,23-四氨基酞菁铜(II) (Cu(II)TAPc) 为载体制备PVC聚合膜,构建了水杨酸根选择性电极,并探讨了该电极的选择性响应性能。研究了增塑剂的性质、载体的含量及阴、阳离子添加剂对电极电位响应的影响。结果表明,基于Cu(II)TNPc为载体的PVC膜电极对水杨酸根 (Sal-) 呈现出优先选择性电位响应。具有最佳电位响应的电极的膜组成是:(w/w) 3.0% Cu(II)TNPc,67.0% o-NPOE,29.5% PVC和0.5% NaTPB。基于该组成的电极的线性响应范围为1.0×10-1-9.0×10-7 mol·L-1,检测下限为7.2×10-7 mol·L-1,斜率为-59.8±0.5 mV/decade;其响应快速,稳定性好,适宜的pH范围是3.0-7.0。并成功运用于了实际样品中水杨酸含量的测定,获得令人满意的结果。  相似文献   

15.
Complexing polymer‐coated electrodes have been synthesized by oxidative electropolymerization of ethylenediamine tetra‐N‐(3‐pyrrole‐1‐yl)propylacetamide (monomer L ). The presence of four polymerizable pyrrole fragments on the same EDTA skeleton was thought to confer enhanced rigidity and controlled dimensionality to the resulting complexing materials, which were used for the electrochemical detection of Hg(II), Cu(II), Pb(II) and Cd(II) ions by means of the chemical preconcentration‐anodic stripping technique. The polyamide electrode material showed particularly a significant selectivity towards mercury ions, even in the presence of a large excess of other metal cations. Moreover, the use of imprinted polymer‐coated electrodes prepared by electropolymerization of L in the presence of metal cations turned out to significantly improve the detection limits, down to 5×10?10 mol L?1 for Hg(II) and Cu(II) species.  相似文献   

16.
Stable water‐soluble CdHgTe nanorods with an emission wavelength at 722 nm, obtained by doping Hg2+ into CdTe nanorods, has been used as a near‐infrared region (NIR) probe to investigate their interaction with copper(II) ions. A new fluorimetric method for the determination of copper(II) ions has been developed based on the quenching effect of copper(II) ions on the emission of CdHgTe nanorods. The mechanism studies show that an effective electron transfer from nanorods to the copper(II) ions occurred based on the coordination reaction between copper(II) ions and the carboxyl groups on the nanorods surface, which could be responsible for the emission quenching of CdHgTe nanorods. Under optimum conditions, the linear range of the calibration curve for the determination of Cu2+ is from 8.0×10?9 to 1.0×10?6 mol/L and the detection limit is 2.0×10?9 mol/L. Owing to low background interference of NIR measurement, the proposed method displays relative high sensitivity and selectivity. Especially, some physiologically important cations almost do not interfere with the determination of Cu2+. The proposed method was also applied to the determination of trace Cu2+ in real aqueous samples with satisfactory results.  相似文献   

17.
《Analytical letters》2012,45(13):2562-2573
Abstract

A sensing system for uracil was constituted by using lanthanum hydroxide nanowires (LNW) as a modifier to obtain LNW modified carbon paste electrode (LNW/CPE) and by introducing copper(II) ion into supporting electrolyte to transform electroinactive uracil to electroactive uracil‐Cu(II) complex. The voltammetric behaviors of uracil in the presence of Cu(II) ion at LNW/CPE were investigated. A reduction peak of the uracil‐Cu(II) complex at ?0.18 V was the two‐electron reduction of Cu(II) ion in the uracil‐Cu(II) complex; while a new oxidation peak at 0.22 V was the one‐electron oxidation of the uracil‐Cu(I) complex. Additionally, the voltammetric responses of all the complexes at LNW/CPE were more sensitive than that at carbon and multiwall carbon nanotube paste electrodes, which resulted from both the large surface effect of LNW and the chemical coordination of uracil with La(III) ion in LNW. With the sensitive oxidation peak of the uracil‐Cu(I) complex at LNW/CPE, a linear range of 4.0×10?9?3.0×10?8 mol/l for uracil was obtained along with a detection limit of 2.0×10?10 mol/l. The proposed system was evaluated by the determination of uracil derivatives, anticancer drug 5‐flurouracil, in pharmaceutical preparations.  相似文献   

18.
《Analytical letters》2012,45(5):890-901
Abstract

A highly selective polyvinyl chloride (PVC) membrane electrode, based on N,N′‐(aminoethyl)ethylenediamide bis(2‐benzoideneimine) binuclear copper(II) complex [Cu(II)‐AEBB] as neutral carrier, was prepared for thiocyanate (SCN?) determination, which displays an anti‐Hofmeister selectivity sequence for a series of anions in the following order: SCN?>ClO4 ?>Sal? > I?>NO3 ?>Br?> Cl?>NO2 ?>SO3 2?>F?>H2PO4 ?>SO4 2?. The electrode exhibited near‐Nernst response for SCN? with a slope of –59.0 mV/decade over a wide concentration range (8.5×10?7~6.8×10?1 mol/L) with a detection limit of –5.0×10?7 mol/L in pH 5.0 phosphate buffer solution at 25°C. Alternating current (AC) impedance and equivalent circuits were used to investigate the thiocyanate response mechanism of the membrane doped with [Cu(II)‐AEBB].  相似文献   

19.
A new preconcentration method is presented for lead on TAN‐loaded polyurethane foam (PUF) and its measurement by differential pulse anodic stripping voltammetry (DPASV). The optimum sorption conditions of 1.29 × 10?5 M solution of Pb(II) ions on TAN‐loaded PUF were investigated. The maximum sorption was observed at pH 7 with 20 minutes equilibrated time on 7.25 mg mL?1 of TAN‐loaded foam. The kinetic study indicates that the overall sorption process was controlled by the intra‐particle diffusion process. The validity of Freundlich, Langmuir and Dubinin ‐ Radushkevich adsorption isotherms were tested. The Freundlich constants 1/n and KF are evaluated to be 0.45 ±0.04 and (1.03 +0.61) × 10?3 mol g?1, respectively. The monolayer sorption capacity and adsorption constant related to the Langmuir isotherm are (1.38 ± 0.08) × 10?5 mol g?1 and (1.46 ± 0.27) × 105 L mol?1, respectively. The mean free energy of Pb(II) ions sorption on‐TAN loaded PUF is 11.04 ± 0.28 kJ mol?1 indicating chemisorption phenomena. The effect of temperature on the sorption yields thermodynamics parameters of ΔH, ΔS and ΔG at 298 K that are 15.0 ± 1.4 kJ mol?1, 74 ±5 J mol?1 K?1 and ‐7.37 ± 0.28 kJ mol?1, respectively. The positive values of enthalpy (ΔH) and entropy (ΔS) indicate the endothermic sorption and stability of the sorbed complexes are entropy driven. However, the negative value of Gibb's free energy (ΔG) indicates the spontaneous nature of sorption. On the basis of these data, the sorption mechanism has been postulated. The effect of different foreign ions on the sorption and desorption studies were also carried out. The method was successfully applied for the determination of lead from different water samples at ng levels.  相似文献   

20.
A new modified carbon paste electrode (CPE) based on a recently synthesized ligand [2‐mercapto‐5‐(3‐nitrophenyl)‐1,3,4‐thiadiazole] (MNT), self‐assembled to gold nanoparticles (GNP) as suitable carrier for Cd(II) ion with potentiometric method are described. The proposed electrode exhibits a Nernstian slope of 29.4±1.0 mV per decade for Cd(II) ion over a wide concentration range from 3.1×10?8 to 3.1×10?4 mol L?1. The detection limit of electrode was 2.0×10?8 mol L?1 of cadmium ion. The potentiometric responses of electrode based on MNT is independent of the pH of test solution in the pH range 2.0–4.0. It has quick response with response time of about 6 s. The proposed electrode show fairly good selectivity over some alkali, alkaline earth, transition and heavy metal ions. Finally, the proposed electrode was successfully employed to detect Cd(II) ion in hair and water samples.  相似文献   

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