Catalytic Kinetic Determination of Trace Amounts of Copper with Polarographic Detection

Abstract

This method is based on the catalytic effect of copper(II) on the redox reaction between acid chrome dark blue and ascorbic acid in acetic acid-sodium acetate buffer solution and 1,10-phenanthroline as an activator. Acid chrome dark blue exhibits a sensitive polarographic wave at -0.375V Vs. SCE and change of acid chrome dark blue concentration is traced by a polarographic detection technique. The detection limit and the linear range of copper(II) are 2.34ng/ml and 5 to 50ng/ml respectively. This new catalytic method has been applied to the determination of copper in human hair, with satisfactory results.     

催化动力学极谱法测定痕量钼

在稀Ｈ２ＳＯ４介质中，钼（Ⅵ）对硫酸联氨还原乙基橙的反应有强烈的催化作用。建立了催化动力学极谱法测定痕量钼的新体系，方法线性范围为２０－３００ｎｇ／ｍＬ，检出限为３．５４ｎｇ／ｍＬ。方法应用于尿中中钼的测定，结果满意。     

甲苯胺蓝褪色指示反应动力学光度法测定痕量铁

研究了在硫酸介质中 ,痕量铁催化 H2 O2 和 K2 Cr O7联合氧化甲苯胺蓝褪色反应及其动力学条件 ,建立了催化动力学测定痕量铁的新方法。检出限为9.6 6× 10 -9g· m L-1 ,测定的线性范围为 0～ 0 .6μg/2 5 m L。方法已用于矿泉水、莱服子、菊花、大米和花生中铁的测定     

催化动力学分光光度法测定微量铁的研究

在 Na2 HPO4介质中 ,研究了 Fe( )催化 H2 O2 氧化甲基百里酚蓝褪色指示反应及其动力学条件 ,建立了测定痕量铁的新方法。方法的线性范围为 0 .0 2～ 0 .2 5μg/2 5m L,检出限为 0 .0 1 2 μg/2 5m L。用以测定过氧化碳酸钠 ( 2 Na2 CO3· 3H2 O2 )中的铁 ,结果令人满意。     

催化动力学极谱法测定痕量亚硝酸根

在硫酸介质中，痕量亚硝酸根对溴酸钾氧化酸性铬深蓝的反应有极强的催化作用，研究了最佳反应条件，发现在氨缓冲溶液中酸性铬深蓝具有良好的极谱峰，以极变法监测催化反应过程中酸性铬深蓝浓度的变化，建立了催化动力学极谱法测定痕量亚硝酸根的方法，方法的线性范围为0．20－1．34μg.ml^-1，检出限为0．088μg.ml^-1，应用于雪水，雨水中痕量亚硝酸根的测定，结果满意。     

催化荧光法测定痕量铁的研究

本利用Ｆｅ（Ⅲ）与四乙撑五胺协同催化过氧化氢氧化还原型二氯荧光素的反应，提出了测定痕量Ｆｅ（Ⅲ）的新催化荧光方法。方法的线性范围为０．０１－０．３０μｇ／２５ｍｌ，检出限为１．３×１０＾－＾１＾０ｇ／ｍｌ，常见离子不干扰测定。用于人发，指甲，血清和面粉中痕量铁的测定，回收率为９７％－１０４％。     

Catalytic Kinetic Determination of Trace Amounts of Palladium with Photometric Detection

 A new, simple photometric method for the determination of palladium was described. Palladium was determined photometrically at 600 nm and pH = 5.4 based on its heterogeneous catalytic effect on the reduction of thionine (TN) with hypophosphite (HP) using a probe-type photometer system (variable time method). The influence of reaction variables was discussed. The calibration curve was found linear in the range 0.11–5.55 μg/ml (at 30 °C) and the detection limit was 0.06 μg/ml. The relative standard deviation of the developed method was 1.6% (for 10 replicate determinations of 2.22 μg/ml Pd(II)). The effect of interference from other metal ions and anions was studied. The proposed method was successfully applied to catalysts, Pd–C, Al–Si–Pd (new and used). Received March 1, 2001 Revision August 10, 2001     

Simultaneous Polarographic Determination of Iron (II) and Iron (III) in Coal Mine Waste Water

Abstract

Polarography with a sodium carbonate-oxalic acid supporting electrolyte was used to determine both Fe(II) and Fe(III) simultaneously in actual coal mine water samples. The average relative percent error was 2.2% for Fe(II) and 2.1% for Fe(III) over a range of 10 to 500 ppm. In actual mine water the Fe(II) content was highest where the mine water emerged. As the water moved down stream from the source of pollution Fe(II) decreased and Fe(III) concentration increased as Fe(II) was oxidized to Fe(III) by oxygen. This was accompanied by a decrease in pH. Further down the stream Fe(III) started to precipitate and then its concentration steadily decreased.     

二溴对甲基偶氮羧催化动力学光度法测定岩石及粮食中铁

研究了痕量铁对高碘酸钾氧化二溴对甲基偶氮羧的催化作用 ,发现其在H2 SO4 介质中具有高灵敏的反应 ,检出限为 8.2 2× 1 0 -11g/m L,线性范围为 Fe( ) 0～ 0 .1 8μg/2 5m L。可用于测定岩石及粮食中的铁     

催化动力学光度法测定痕量甲醛

基于在硫酸介质中,甲醛对溴酸钾氧化甲基橙褪色反应的催化作用,建立了测定痕量甲醛的催化动力学光度法。在选定的条件下,方法的线性范围为0~0.16 mg/L,表观摩尔吸光系数为1.18×105L.mol-1.cm-1,检出限为2.8μg/L。利用此法测定了饮料、废水和空气中的痕量甲醛,测定结果的相对标准偏差(RSD)小于5%(n=5),回收率为93%~106%,结果满意。     

催化褪色光度法测定牡蛎中痕量铁

采用催化褪色光度法测定牡蛎中痕量铁，以获得牡蛎生长过程中富集重金属的信息。Ｆｅ（Ⅲ）在硫酸介质中能催化过氧化氢氧化甲基红的反应，并研究了影响褪色反应速度的最佳条件，方法的灵敏度为６×１０－１１ｇ／ｍＬ，测定范围为０～０．０４８μｇ／ｍＬＦｅ（Ⅲ）。方法简便，有较高的选择性。     

Iron(II) and iron(III) complexes containing ethynyl thiophene fragments

The synthesis of the new complexes Cp*(dppe)FeCC2,5-C₄H₂SR (Cp* = 1,2,3,4,5-pentamethylcyclopentadienyl; dppe = 1,2-bis(diphenylphosphino)ethane; 2a, R = CCH; 2b, R = CCSi(CH₃)₃; 2c, R = CCSi(CH(CH₃)₂)₃; 3a, R = CC2,5-C₄H₂SCCH; 3c, R = CC2,5-C₄H₂SCCSi(CH(CH₃)₂)₃) is described. The ¹³C NMR and FTIR spectroscopic data indicate that the π-back donation from the metal to the carbon rich ligand increases with the size of the organic π-electron systems. The new complexes were also analyzed by CV and the chemical oxidation of 2a and 3c was carried out using 1 equiv of [Cp₂Fe][PF₆]. The corresponding complexes 2a[PF₆] and 3c[PF₆] are thermally stable, but 2a[PF₆] was too reactive to be isolated as a pure compound. The spectroscopic data revealed that the coordination of large organic π-electron systems to the iron nucleus produces only a weak increase of the carbon character of the SOMO for these new organoiron(III) derivatives.     

催化动力学光度法测定痕量铁的研究进展

综述了催化动力学光度法测定痕量Fe(Ⅲ)的研究进展，分别从催化氧化(还原)动力学、阻抑动力学和催化荧光光度法等几个类别进行归纳，并从反应介质、检出限、线性范围和应用等方面进行叙述．     

Voltammetric Determination of Iron(III) in Water

A square wave voltammetric procedure for the determination of trace amounts of Fe(III) was developed at an unmodified edge plane pyrolytic graphite (EPPG) electrode and a screen printed electrode (SPE). This simple procedure was applied to real samples of commercially bottled mineral water. Sensitive results in the micromolar region could be achieved without modification of the electrode. Using the WHO guideline limits for the Fe(III) concentration in drinking water, recovery percentages at an EPPG gave 103 % and 107 %, and 98.6 % and 95.0 % at a SPE for the 5.36 µM (0.3 mg L^?1) and 53.6 µM (3.0 mg L^?1) additions of Fe(III), respectively.     

催化动力学光度法间接测定水中痕量硫离子

在氨水介质中,硫离子可阻抑Fe(Ⅲ)催化过氧化氢氧化二甲酚橙褪色,并且催化体系和阻抑体系在570 nm处吸光度的差值与硫离子浓度呈线性关系,据此建立了阻抑动力学光度法间接测定痕量硫离子的新方法。方法的线性范围为0.0020~0.044mg/L,检出限为1.6×10-9g/mL,对0.040 mg/L硫离子进行10次平行测定的相对标准偏差为2.1%。方法用于废水中硫离子的测定,结果满意。     

Determination of Molybdenum(VI) At Trace Levels by a Catalytic Polarographic Method

Abstract

ARSTRACT

A d.c. polarography method for molybdenum (VI) determination at trace levels has been developed. The reaction is catalytic between molybdenum, salicylaldoxime (SCAD) and bromate in acetic-acetate medium. The obtained peak is proportional to molybdenum (VI) concentrations in the range 1.08.10^?a to 1.37.10^?6 M. The proposed procedure is selective, the most serious interferents being W(VI), Pb(II) and Fe(II). It is applied to molybdenum determination in steel samples after iron extraction by ethyl ether.     

流动注射催化动力学荧光法测定痕量钌

利用2-吡啶甲醛和苯甲酰肼合成了一种新的荧光试剂2-吡啶甲醛苯甲酰腙,对其进行了红外光谱和元素分析,证明了目标化合物的生成。运用2-吡啶甲醛苯甲酰腙-KBrO3这一反应体系为指示反应,采用正相流动注射2-吡啶甲醛苯甲酰腙乙醇水溶液试剂作为载流,注入样品(钌溶液)进行实验,发现2-吡啶甲醛苯甲酰腙被KBrO3氧化后荧光增强,Ru3 是极好的催化剂。据此,研究了该指示反应的适宜条件,共存离子的影响,并探讨了反应机理,建立了快速、简便、高灵敏度、高选择性流动注射催化动力学荧光测定钌的方法,检出限0.60μg/L,线性范围2.0~400μg/L。本方法成功地应用于人工合成样及矿样中痕量钌的测定。     

Iron(III) chloride and its coordination chemistry

Abstract

The coordination chemistry of FeCl₃ is distinctly different to that of the other 3d metal halides. It has a distinct preference for O-donor ligands. Although it primarily forms six-coordinate complexes, it has some distinctive features that set it apart from metals like Mn(II), Co(II), and Ni(II), such as the self-ionized complexes [FeL₄Cl₂]⁺ [FeCl₄]^?. There are a number of examples where very small changes in the coordination sphere tilt the balance between isomeric structures. Chloride has a significant steric effect in the coordination sphere as well as a greater trans-influence than water.     

Simple,Selective, and Sensitive Spectrophotometric Method for Determination of Trace Amounts of Nickel（Ⅱ）, Copper （Ⅱ）, Cobalt （Ⅱ）, and Iron （Ⅲ） with a Novel Reagent 2-Pyridine Carboxaldehyde Isonicotinyl Hydrazone

A selective and sensitive reagent of 2-pyridine carboxaldehyde isonicotinyl hydrazone（2-PYAINH） was synthesized and studied for the spectrophotometric determination of nickel, copper, cobalt, and iron in detail. At a pH value of 7.0, 9,0, 9.0, and 8.0, respectively, which greatly increased the selectivity; nickel, copper, cobalt, and iron reacted with 2-PYAINH to form a 1：2 yellow-orange, 1：2 yellow-green, 1：2 yellow and 1：1 yellow complexes, with absorption peaks at 363, 352, 346, and 359 nm, respectively. Under the optimal conditions, Beer＇s law was obeyed over the ranges of 0.01-1.4, 0.01-1.5, 0.01-2.7, and 0.01-5.4 mg/L respectively. The apparent molar absorptivity and Sandell＇s sensitivities were 8.4×10^4, 5.2×10^4, 7.1×10^4, and 3.9×10^4 L·mol^-l·cm^-1, respectively, and 0.00069, 0.0012, 0.00078, and 0.0014 μg·cm2, respectively. The detection limits were found to be 0.001, 0.002, 0.003, and 0.01 mg/L, respectively. The detailed study of various interfering ions to make the method more sensitive was carried out and selective and several real samples were analyzed with satisfactory results.