Development and Validation of Catalytic Kinetic Spectrophotometric Method for Determination of Copper(II)

A catalytic kinetic spectrophotometric method is developed for the determination of trace amounts of Cu(II). It is based on the catalytic effect of Cu(II) on the oxidation of cysteine (RSH) by hexacyanoferrate(III) in acidic medium. The reaction was monitored spectrophotometrically by measuring the decrease in absorbance of hexacyanoferrate(III) at 420nm. The optimum operating conditions regarding concentration of reagents, pH and temperature were established. The working curve is linear in the concentration range of 0–6.35ng·mL^–1. The maximum percentage error and standard deviation for determination of Cu(II) in the range of 1.27–6.35ng·mL^–1 have been calculated to be 3.9 and 0.4 respectively. The detection limit calculated was 0.15ng·mL^–1. The interference effect of several species was also investigated, and it was found that the most common cations and anions do not interfere with the determination. The developed procedure was successfully applied to the determination of Cu(II) in various synthetic and real samples. The typical feature of this procedure is that determination can be carried out at 25°C and/or in the absence of any precision thermostatic bath in the very short analysis time of one minute. The newly developed method was found to have fairly good selectivity, sensitivity, simplicity and rapidity compared to other kinetic methods.Received October 8, 2002; accepted April 7, 2003 Published online July 16, 2003     

Chemiluminescence in the reduction of XeO3 by europium(II)

Chemiluminescence has been observed in the reduction of perchloric aqueous solutions of XeO₃ with Eu²⁺ ions, Fast (several seconds) consumption of Eu^II occurs when the ratio of the initial concentrations of the reactants (Eu²⁺]₀ : [XeO₃]₀ < 6; however, the chemiluminescence remains sufficiently bright and prolonged (up to –10 min after nearly complete oxidation of Eu^II to Eu^III). The assumption was made that intermediates in the reduction of XeO₃ participate in the chemiluminescent stages of the process.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2909–2911, December, 1996.     

Novel Polymeric Membrane Sensors Based on Mn(III) Porphyrin and Co(II) Phthalocyanine Ionophores for Batch and Flow Injection Determination of Azide

Two novel potentiometric azide membrane sensors based on the use of manganese(III)porphyrin [Mn(III)P] and cobalt(II)phthalocyanine [Co(II)Pc] ionophores dispersed in plasticized poly(vinyl chloride) PVC matrix membranes are described. Under batch mode of operation, [Mn(III)P] and [Co(II)Pc] based membrane sensors display near‐ and sub‐Nernstian responses of ?56.3 and ?48.5 mV decade^?1 over the concentration ranges 1.0×10^?2?2.2×10^?5 and 1.0×10^?2?5.1×10^?5 mol L^?1 azide and detection limits of 1.5×10^?5 and 2.5×10^?5 mol L^?1, respectively. Incorporation of both membrane sensors in flow‐through tubular cell offers sensitive detectors for flow injection (FIA) determination of azide. The intrinsic characteristics of the [Mn(III)P] and [Co(II)Pc] based detectors in a low dispersion manifold show calibration slopes of ?51.2 and ?33.5 mV decade^?1 for the concentration ranges of 1.0×10^?5?1.0×10^?2 and 1.0×10^?4?1.0×10^?2 mol L^?1 azide and the detection limits are1.0×10^?5 and 3.1×10^?5 mol L^?1, respectively. The detectors are used for determining azide at an input rate of 40–60 samples per hour. The responses of the sensors are stable within ±0.9 mV for at least 8 weeks and are pH independent in the range of 3.9?6.5. No interferences are caused by most common anions normally associated with azide ion.     

Coprecipitation of Amino Acids with Mixed Hydroxide of Iron(III) and Copper(II)

Abstract

A coprecipitation method for concentrating amino acids from aquatic environments with a mixed hydroxide of iron(III) and copper(II) was developed. The percent coprecipitation of glycine, alanine, glutamic acid, aspartic acid, and lysine, being independent of pH in the range of 8.5 to 9.5, was more than 95%.     

Chemiluminescence Flow Injection Determination of Copper (II)

ABSTRACT

A sensitive and selective flow injection chemiluminescence method for the determination of copper over the range of 0.5-7.5 ng is described. The method is based on quenching effect of copper (II) on the chemiluminescent reaction of dichlorofluorescein and hydrogen peroxide in alkaline media. Method development includes optimization of reagent concentrations and flow conditions. The optimized method yielded a detection limit (3σ) of 0.2 ng. The method is simple, fast, selective and precise and was used for the determination of copper in blood sera.     

Determination of Rifampicin by Peroxomonosulfate‐Cobalt(II) Chemiluminescence System

Rifampicin can enhance the chemiluminescence (CL) of peroxomonosulfate‐cobalt(II) system, and the CL intensity is strongly dependent on the rifampicin concentrations. Based on this phenomenon, a rapid and sensitive flow injection CL method was developed for the determination of rifampicin. The relative CL intensity was linear with the rifampicin concentration over the range of 5×10^?8 to 1×10^?6 g·mL^?1 (r=0.9991), the detection limit was 7×10^?9 g·mL^?1 (S/N=3), and the relative standard deviation was 2.7% for 6×10^?7 g·mL^?1 rifampicin (n=11). Furthermore, this method was successfully applied to the determination of rifampicin in real eye drop and capsules sample.     

Analytical Use of Copper (II)-Neocuproine in The Spectrophotometric Determination of Hydrazines

Abstract

This work characterizes a newly developed, sensitive and convenient spectrophotometric procedure for determination of sub-ppm concentrations of hydrazine and its organic derivatives. The method is based on formation of the cuprous neocuproine chelate after reaction of hydrazines with a prepared aqueous solution of the copper (II)-neocuproine complex. The cuprous chelate is then directly measured in aqueous solution at 458 nm. The effect of several experimental conditions influencing the reaction are presented and the method was employed for the analyis of 5 different hydrazine compounds. The standard deviation did not exceed ± 0.47%.     

Determination of Fe(II), Cu(II) and Ag(I) by using silica gel loaded with 1,10-phenanthroline

The modified silica gel with 1,10-phenanthroline adsorbed was obtained. The adsorption from aqueous solutions onto loaded silica gel of Fe(II), Cu(II) and Ag(I) and their complexes was studied. The loaded silica gel was applied to Fe(II), Cu(II) and Ag(I) reflectance spectroscopy determinations in water (detection limits 0.08, 0.03 and 0.01 ppm respectively). Visual test scales for Fe, Cu and Ag ion determinations in water were worked out.     

meso-四(邻烷氧基苯基)卟啉及其铜配合物的合成、表征和性能研究

合成了meso-四(邻烷氧基苯基)卟啉及其铜配合物两个系列20个化合物, 其中未见文献报道的化合物16个, 研究了其合成、分离、纯化方法, 得到了这两个系列化合物的晶体或固体, 用¹H NMR, MS, IR, UV, 元素分析等方法确证了这些化合物的结构. 用差示扫描量热法(DSC)和偏光显微镜(PM)研究了这两个系列化合物的液晶性能, 发现19个化合物具有液晶性, 其液晶行为表现为升温单变液晶.     

微波辅助原位生成水溶性Salen-Cu(II)配合物催化水中的两步一锅法click反应

本文报道原位生成的水溶性Salen-Cu(II)配合物(N,N’-双(亚甲基-2-羟基-5-苯磺酸钠)缩-N,N’-二甲基乙二胺合铜)催化微波加热的水中的两步一锅法click反应。在优化反应条件之后,对碘苯及其衍生物、叠氮化钠与苯乙炔及其衍生物的两步一锅法click反应和卤代烷、叠氮化钠与苯乙炔的三组分两步一锅法click反应进行了考察。在所选择的条件下,这两类click反应都能获得很好的收率,与常规加热模式的三组分两步一锅法click反应相比较,微波加热的显示出了特别高的反应效率。     

四(4-三甲铵苯基)卟啉荧光熄灭法测定痕量镉(Ⅱ)

利用TPPS₄催化动力学荧光测定痕量镉(Ⅱ)已有报道^[1],而利用四(4-三甲铵苯基)卟啉(TAPP)的荧光熄灭测定痕量镉(Ⅱ)的工作尚未见报道.本文研究了室温下Cd(Ⅱ)-TAPP反应体系的荧光光谱特性,发现Cd(Ⅱ)-TAPP的形成使TAPP的荧光发生静态熄灭.利用咪唑(Imid)、十二烷基硫酸钠(SDS)和乙醇增敏、增稳,最低可检测3×10^-4ppmCd(Ⅱ),灵敏度高于其它方法^[2].测定了胶印锌片和人发中的镉,结果与标准值或方法对照值吻合.     

Chemiluminescence Determination of Sulfite and Sulfur Dioxide Using Tris(1,10-Phenanthroline)Ruthenium-KMnO4 System

Abstract

The emission produced by sulfite after oxidation by potassium permanganate in acidic solution in the presence of Ru(phen)₃ ²⁺ is used to determine 1.0 × 10^?7 to 2.5 × 10^?5 mol/L sulfite. The limit of detection is 4.5 × 10^?9 mol/L and the relative standard deviation is 3.1% for a 1 × 10^?5 mol/L sulfite solution (n=8). The method was also applied satisfactorily to the determination of sulfur dioxide in air by using triethanolamine (TEA) as absorbent material.     

Preparation and Thermal Decomposition of Copper(II) Complexes with 4-Methylimidazole

Simple and mixed compounds of the formulae Cu(4-Meim)₂, CuSal(4-Meim), CuSal(4-Meim)₂ and CuSalox(4-Meim)₂, where 4-Meim=4-methylimidazole, Sal=(OC₆H₄COO)²⁻, Salox=(OC₆H₄CHNO)²⁻ have been prepared. Thermal decomposition reactions have been established on the basis of thermal and X-ray analyses of these compounds. The pyrolysis proceeds in several (3–4) stages connected with the mass loss and exothermic effects. As a result of the last stage of decomposition CuO is formed. This revised version was published online in August 2006 with corrections to the Cover Date.     

Thermal Studies of Copper(II) Squarate Complexes of Diamines in the Solid State

CuL₂C₄O₄ [L=ethane-1,2-diamine (en)], CuL₂C₄O₄⋅2H₂O [L=N-methylethane-1,2-diamine (meen), N-ethylethane-1,2-diamine (eten),N-propylethane-1,2-diamine (pren), N-methyl-N’-ethylethane- 1,2-diamine (meeten) andpropane-1,2-diamine (pn)], CuL₂C₄O₄⋅0.5H₂O [L=N,N’-dimethylethane- 1,2-diamine (dmeen)], CuL₂C₄O₄⋅4H₂O [L=propane-1,2-diamine (pn)]and CuL₂C₄O₄⋅H₂O[L=2-methylpropane-1,2-diamine (ibn)] have been synthesized by the addition of respective diamine to finely powdered CuC₄O₄⋅2H₂O and their thermal studies have been carried out in the solid state. Cu(en)₂C₄O₄ upon heating loses one molecule of diamine with shar pcolour change yielding Cu(en)C₄O₄ which upon further heating transforms to unidentified products. All aquated-bis-diamine species [CuL₂C₄O₄⋅2H₂O, CuL₂C₄O₄⋅0.5H₂O and CuL₂C₄O₄⋅H₂O] upon heating undergo deaquation–anation reaction in the solid state showing thermochromism and transform to CuL₂C⁴O₄, which revert on exposure to humid atmosphere (RH ∼90%). All the squarato bis-diamine species, CuL₂C₄O₄, on further heating transform to unidentified products through the formation of CuLC₄O₄ as intermediates. The mono diamine species, have been isolated pyrolytically in the solid state and can be stored in a desiccator as well as in open atmosphere. They are proposed to be polymeric. This revised version was published online in August 2006 with corrections to the Cover Date.     

Selective Detection of Mercury（Ⅱ） and Copper（Ⅱ） Based on the Opposite Size-dependent Fluorescence Quenching of CdTe Quantum Dots

Three different size CdTe quantum dots （QDs） capped by 3-mercaptopropionic acid （MPA） have been prepared in aqueous solutions, and their interactions with Cu^2＋ and Hg^2＋ have been investigated. The opposite size-dependent fluorescence quenching of CdTe QDs by Hg^2＋ and Cu^2＋ was observed： Hg^2＋ quenched smaller particles more efficiently than larger ones while larger particles were more markedly quenched by Cu^2＋. Based on the different size responses, Hg^2＋ and Cu^2＋ were respectively detected with high sensitivity and selectivity, for the first time, using the QDs with different sizes but the same components and capping ligands.     

Simple and Simultaneous Method for Determination of Palladium(II) and Ruthenium(III) using Second-Order-Derivative Spectrophotometry

Abstract

A simple, sensitive, and selective second-order-derivative spectrophotometric method has been developed for the simultaneous determination of palladium(II) and ruthenium(III) using 2-hydroxy-3-methoxy benzaldehyde thiosemicarbazone (HMBATSC) as a chromophoric reagent. The reagent (HMBATSC) reacts with Pd(II) and Ru(III) at pH 3.0, forming soluble yellowish green and dark brown species, respectively. Palladium and ruthenium present in the mixture were simultaneously determined without solving the simultaneous equations by measuring the second derivative amplitudes at 445 nm and 385 nm, respectively. Further, the Beer's law was obeyed in the range 0.21–12.78 µg mL^?1 and 0.25–13.42 µg mL^?1 for Pd(II) and Ru(III), respectively. A large number of foreign ions did not interfere in the present method. The proposed method was successfully applied for the determination of palladium in hydrogenation catalysts and ruthenium in water samples.     

四氮大环-金属配合物与DNA作用的电化学及谱学研究

Mononuclear copper（Ⅱ）, nickel（Ⅱ） and cobalt（Ⅲ） tetracoordinate macrocyclic complexes were synthesized and spectroscopically characterized. The crystal structure of the three compounds were determined by X-ray crystallography. The electrochemical experimental results indicate that the three complexes could interact with DNA mainly by electrostatic interaction. The interaction of tetracoordinate macrocyclic cobalt（Ⅲ） complex with DNA was studied by cyclic voltammetry and UV-vis spectroscopy. The experimental results reveal that tetracoordinate macrocyc- lic cobalt（Ⅲ） complex could interact with DNA by electrostatic interaction to form a 1 ： 1 DNA association complex with a binding constant of 7.50 ×10^3 L·mol^-1.     

Conductometric Determination of N-acetylcysteine in Pharmaceutical Formulations Using Copper(II) Sulphate as Titrant

Abstract

A simple, precise, rapid, and low-cost conductometric method for N-acetylcysteine determination in pharmaceutical formulations is proposed. N-acetylcysteine present in pharmaceuticals containing known quantities of the drug was conductometrically titrated in aqueous solution with copper(II) sulphate using a conductometric cell coupled to an autotitrator. No interferences were observed in the presence of common components of the tablets such as sodium monophosphate, saccharine, sodium benzoate, sucrose, and fructose. Recoveries of N-acetylcysteine from various tablet dosage formulations ranging from 98.3 to 102.0% were obtained.     

Thermal Investigation of the Compounds of the Copper(II) Mono(o-hydroxybenzoate) with Chelate Ligands

Heteroligand complexes of copper(II) were obtained as a result of the reaction of Cu(II) mono (o-hydroxybenzoate) (monohydrate) with 8-hydroxyquinoline (HOx), o-aminophenol (NH₂Ph) and 2,2′-dipyridyl (2,2′-dipy). The mixture of the mono compound with: Cu(II) di(o-aminobenzoate) or Cu(II) di(o-hydroxybenzaldoximate) were obtained by the reaction with o-aminobenzoic acid (H₂A) and o-hydroxybenzaldoxime (H₂Salox). The obtained compounds and their sinters were subjected to chemical, X-ray and thermal analyses. This revised version was published online in July 2006 with corrections to the Cover Date.     

Construction of Modified Carbon Paste Electrode for Highly Sensitive Simultaneous Electrochemical Determination of Trace Amounts of Copper (II) and Cadmium (II)

A chemically modified electrode was constructed for rapid, simple, accurate, selective and highly sensitive simultaneous determination of Cu(II) and Cd(II) using square wave anodic stripping voltammetry. The electrode was prepared by incorporation of SiO₂ nanoparticles, coated with a newly synthesized Schiff base, in carbon paste electrode. The limit of detection was found to be 0.28 ng mL^?1 and 0.54 ng mL^?1 for Cu(II) and Cd(II), respectively. The proposed chemically modified electrode was used for the determination of copper and cadmium in several foodstuffs and water samples.