Determination of ni,zn and al in bronzes and brasses after determining cu-pb-sn-sb by controlled-potential electrolysis

A method is given, which allows nickel, zinc and aluminium to be determined in the solution remaining after the determination of copper, lead, tin and antimony by controlled-potential electrolysis. Nickel is precipitated by dimethylglyoxime, zinc is deposited by controlled-potential electrolysis and aluminium is precipitated first by oxine and then by ammonium benzoate.     

The determination of nickel, zinc, cobalt and manganese impurities in cadmium by pulse polarography

A pulse-polarographic method for the simultaneous determination of traces of nickel, zinc, cobalt and manganese in cadmium and its compounds is described. Interference from the reduction of the cadmium matrix was eliminated by a prior electrolytic deposition of cadmium on a mercury cathode at a controlled potential of –0.90 V vs. S.C.E. Iron in excess interfered with the determination of cobalt and was therefore extracted from the electrolysed solutions. The polarographic determination was performed in 0.1 M lithium acetate -0.025 M lithium thiocyanate as supporting electrolyte. A sample weight of 10 g and a final volume of 10 ml allowed the determination of about 0.08 p.p.m. nickel, 0.01 p.p.m. zinc, 0.02 p.p.m. cobalt and 0.003 p.p.m manganese. Less than 0.01 p.p.m. nickel could be determined with a 0.25 M pyridine 0.05 M potassium chloride supporting electrolyte. Several synthetic samples and commercially available cadmium products were analysed.     

Bismuth film electrode for simultaneous adsorptive stripping analysis of trace cobalt and nickel using constant current chronopotentiometric and voltammetric protocol

Bismuth film electrode (BiFE) is presented as a promising alternative to mercury electrodes for the simultaneous determination of trace cobalt and nickel in non-deoxygenated solutions. The preplated BiFE was employed under adsorptive stripping constant current chronopotentiometric and adsorptive stripping voltammetric conditions in the presence of dimethylglyoxime complexing agent. BiFE exhibited well-defined and undistorted signals with favorable overall resolution for cobalt and nickel cations, with the signals for both metal cations being practically independent of each other. The stripping performance of BiFE is characterized by good reproducibility (RSD 1.4% for Co(II), and 4.3% for Ni(II)), low detection limits of 0.08 μg l⁻¹ for Co(II) and 0.26 μg l⁻¹ for Ni(II) employing a deposition time of 60 s, in addition to good linearity. The non-toxic character of bismuth imparts the possibility of tailoring disposable and one-shot electrochemical sensors for decentralized environmental, clinical and industrial monitoring of trace cobalt and nickel.     

Analytical Application of Silica Gel Modified with Didecylaminoethyl-beta-Tridecylammonium Iodide

Sorption of a high molecular weight quaternary ammonium salt, didecylaminoethyl-β-tridecylammonium iodide (DDATD) on different types of sorbents was investigated. The nature of reagent adsorption on silica gel was examined by spectroscopic and computer methods. The sorption of anionic metal complexes of cobalt, copper, zinc and manganese on silica gel modified with DDATD was studied. The possibility of recovery of cobalt and copper thiocyanate complexes and their further atomic absorption determination is shown. Modified sorbent was applied to cobalt chemiluminescence and determined in natural water and a nickel preparation (detection limit, 2 μg/l.).     

Application of Total Reflection X-Ray Fluorescence Spectrometry in the Textile Industry

 In the present study, the determination of arsenic, lead, cadmium, chromium, cobalt, copper, nickel, mercury and zinc in various cloth samples produced in Kayseri-Turkey was performed after extraction with artificial sweat solution and decomposition with nitric acid. TXRF is shown to be suitable for the determination of 7 trace elements, down to the 0.001 (cobalt) to 0.004 (copper) mg/kg level in textile extract except for mercury and cadmium. The extractable part of the toxic metals by artificial sweat solution is relatively low. In a few extracts the concentration values of Pb and Ni have exceeded their critical values of 0.2 mg/kg for lead and 1.0 mg/kg for nickel given by ?ko-Tex and determined for babys cloths. In addition, it was observed that the element pattern of textile samples resembled ‘finger print type’, TXRF-spectra. This technique can also be used for the identification of textile sample in forensic investigation. Received April 16, 2001 Revision October 1, 2001.     

Determination of copper,nickel, cobalt,silver, lead,cadmium, and mercury ions in water by solid-phase extraction and the RP-HPLC with UV-Vis detection

A new method for the simultaneous determination of seven heavy metal ions in water by solid-phase extraction and reversed-phase high-performance liquid chromatography (RP-HPLC) was developed. The copper, nickel, cobalt, silver, lead, cadmium, and mercury ions were pre-column derivatized with tetra( m-aminophenyl)porphyrin (T m-APP) to form colored chelates. The metal-T m-APP chelates in 100 mL of sample were preconcentrated to 1 mL by solid-phase extraction with a C(18 )cartridge; an enrichment factor of 100 was achieved. The chelates were separated on a Waters Xterra()RP(18) column by gradient elution with methanol (containing 0.05 mol L(-1) pyrrolidine-acetic acid buffer salt, pH 10.0) and acetone (containing 0.05 mol L(-1) pyrrolidine-acetic acid buffer salt, pH 10.0) as mobile phase at a flow rate of 1.0 mL min(-1) and detected with a photodiode array detector. The detection limits of copper, cobalt, nickel, silver, lead, cadmium, and mercury are 2, 2, 3, 4, 3, 3, and 3 ng L(-1), respectively, in the original sample. The method was also applied to the determination of these metals in water with good results.     

Cathodic stripping voltammetric determination of 2-mercaptobenzothiazole using the catalytic cobalt peak

Previously, thiols have been determined indirectly by cathodic stripping voltammetry (CSV) after accumulation as their mercury and copper(I) salts. Following a previous report of the first use of the catalytic nickel peak (for the determination of cysteine), this paper reports the first use of the catalytic cobalt peak in CSV (for the determination of 2-mercaptobenzothiazole (MBT)): only a very ill-defined catalytic cobalt peak had been observed previously with cysteine, and was unreported. MBT is accumulated at pH 4 (Britton-Robinson buffer) as its cobalt(II) complex at -0.1 V, and is then determined indirectly by observing the reduction of the cobalt(II) in the complex at -0.95 V, i.e., with a much lowered overpotential: hydrated cobalt(II) is reduced at -1.2 V. The peak is catalytic because the thiol released on reduction of the complex complexes further cobalt ions and causes their reduction. The detection limit for the determination of MBT was calculated to be 2.5 x 10(-9) M (3sigma) using an accumulation time of 1 min. The sensitivity is about three times that obtained with the corresponding catalytic nickel peak.     

Atomic Absorption Spectrometry Analysis of Silicates by the Absorption Tube Technique

Abstract

By the combined use of the absorption tube technique and solvent extraction, determination of cadmium, cobalt, copper, iron, lead and nickel in silicate rocks was investigated.

Applicable concentration range was from 0.1 to 1.Oppm for all the elements except cadmium, for which the range was from 0.005 to 0.025ppm. The accuracy and recovery determined by the use of standard samples from the United States National Bureau of Standards and Geological Survey were satisfactory for practical purposes.     

The application of salicylaldoxime in solvent extraction

The extraction of divalent magnesium, manganese, cobalt, nickel, copper, zinc, cadmium, mercury, and lead with solutions of salicylaldoxime in benzene was investigated. The effect of the reagent concentration and particularly the pH of the aqueous phase on the extractability was studied. The application of salicylaldoxime extractions in the separation and determination of various elements is discussed.     

Separation of uranium(VI) and transition metal ions with 4-(2-thiazolylazo)resorcinol by capillary electrophoresis

A capillary electrophoresis method utilizing 4-(2-thiazolylazo)resorcinol (TAR) was developed to separate uranium, cobalt, cadmium, nickel, titanium and copper metal ions. TAR was chosen as the visible absorbing chelating ligand because of its ability to form stable complexes with a wide variety of metals. Several parameters that included pH, electrophoretic run buffer concentration, buffer type and the influence of chelating ligand in the electrophoretic run buffer were examined to determine the best separating conditions. Optimum separation of the six metal chelates was achieved in a 15 mM Na2B4O7-NaH2PO4, pH 8.3 buffer containing 0.1 mM TAR. Method validation included injection and method precision studies as well as detection limit and linear dynamic range determination. High-ppb to low-ppm (w/w ratio) detection limits were achieved with linear dynamic ranges between 0.1 and 75 ppm.     

5-Methyl-7-nitroso-8-hydroxyquinoline and its sensitivity and selectivity towards certain metallic ions

5-Methyl-7-nitroso-8-hydroxyquinoline (5-methyl-7-nitroso-oxine), hitherto undescribed, has been prepared and tested for its sensitivity and selectivity towards various metallic ions at differing pH's. The metals tested include cadmium, ferrous and ferric iron, mercurous and mercuric mercury, lead, nickel, cobalt, thallous thallium, cerous and cerie cerium, copper, chromium, aluminium, zinc, magnesium, vanadium (as vanadate) and gallium. This reagent is comparatively “unsclective” in that it chelates with all the above metals under the conditions employed, and therefore closely follows the behaviour of the parent compound, 8-hydroxyquinoline (oxine). Its average sensitivity is somewhat greater than that of the parent compound, and it shows its greatest sensitivity with. divalent mercury.     

Atom-trapping absorption spectrometry with water-cooled metal collector tubes

Water-cooled metal collector tubes for atom-trapping atomic absorption spectrometry in air—acetylene flames are discussed, particularly for the more volatile elements such as cadmium and selenium which may be less efficiently trapped at the hotter surface of a silica tube. It was found that a nickel tube gave 3 times greater sensitivity than silica for the determination of cadmium but was oniy half as sensitive for the determination of selenium. No atomic absorption signal for copper could be obtained with a nickel collector tube. A copper tube was 3–4 times more sensitive than nickel for cadmium and selenium. Similar effects were observed for cadmium solutions containing 1000 ppm copper or nickel, and for selenium solutions containing 1000 ppm copper, with silica atom-trap tubes, but in both cases better results were obtained when the analyte solution of cadmium or selenium contained the co-element (1000 ppm) than when the cadmium or selenium was measured with a silica tube previously metallized with the co-element.     

Spectrophotometric simultaneous determination of cobalt, copper and nickel using nitroso-R-salt in alloys by partial least squares

Partial least squares modeling as a powerful multivariate statistical tool applied to spectrophotometric simultaneous determination of cobalt, copper, and nickel in aqueous solutions. The concentration range for cobalt, copper and nickel were 0.4-2.6, 0.6-3.4, 0.5-5.5 ppm, respectively. The experimental calibration set was composed with 36 sample solutions using a mixture design for three component mixtures. The absorption spectra were recorded from 470 to 600 nm. The effect of pH on the sensitivity and selectivity was studied according to net analyte signal (NAS). The values of root mean square difference (RMSD) for cobalt, copper and nickel using partial least squares (PLS) were 0.0192, 0.0263 and 0.0446 ppm, respectively. The effects of various cations and anions were investigated. The method was used to determination of cobalt, copper and nickel in two sample alloys based on copper, nickel and cobalt (known as cunico) and based on cobalt, nickel and iron (known as conife).     

Determination of nickel and cobalt in natural waters and biological material by reductive chronopotentiometric stripping analysis in a flow system without sample deoxygenation

The instrumental set-up consists of a thin-layer cell with a glassy carbon working electrode and an inlet valve by means of which six different solutions can be sucked through the cell. The system is controlled by a microprocessor and suction is provided by means of a peristaltic pump. In the first step of the analytical cycle, a mercury film is plated onto the glassy carbon electrode and then the sample solution is allowed into the cell and nickel(II) and cobalt(II) are potentiostatically adsorbed onto the mercury film as their dimethylglyoxime complexes. Nickel(II) and cobalt(II) are then reduced in a medium of 5 M calcium chloride by means of constant current and simultaneously the microprocessor records the potential vs. time behaviour of the working electrode. Finally the mercury film is removed by mild oxidation in an iodine/iodide solution and the glassy carbon surface is cleaned with ethanol and sodium hydroxide prior to the next analytical cycle. The cobalt(II) and nickel(II) concentrations are evaluated by means of a standard addition procedure. The technique was applied to drinking, estuarine and sea water samples. The detection limits on the one sigma level after one minute of potentiostatic adsorption were 9 and 11 ng l^?1 for nickel(II) and cobalt(II), respectively. Nickel(II) and cobalt(II) were determined in reference samples of bovine liver and sea-water sediments after acid digestion. In order to obtain correct cobalt values, it was necessary to reduce cobalt(III) species formed during the acid digestion with sodium tetrahydroborate.     

Omega chrome black blue G as a colorimetric reagent for the microdetermination of various cations

Summary Omega Chrome Black Blue G has been found to be a suitable colorimetric reagent for the detection of cobalt and for the determination of copper, cobalt, cadmium, lead and magnesium. The effects of time, p_H, temperature, and foreign ions on the absorbancy are investigated. The reagent is practically suitable for the determination of microgram amounts of cobalt in presence of nickel and other ions which evoke a red colour.The reagent is not suitable for the determination of nickel, calcium, strontium, and zinc.     

Cation analysis by thin-layer chromatography and reflectance spectroscopy : Part II. The determination of copper,nickel and zinc

A method has been developed whereby micro quantities of copper, nickel and zinc resolved on cellulose chromatoplates can be analyzed in situ by means of reflectance spectroscopy. Copper and nickel were determined in the presence of 11 other cations without any interference by employing neocuproine and dimethylglyoxime, respectively, as chromogenic reagents. In the case of zinc, the use of 3,3'-dimethyl-naphthidine was equally successful except in the presence of tin, cadmium and iron. Deviations to be expected when the procedure is employed routinely to determine nickel, copper and zinc, were estimated to be 2.1, 2.8 and 5.6%, respectively.     

电感耦合等离子体发射光谱法（ICP—AES）测定红糖中的微量元素

目的红糖人药胜过白砂糖和冰糖,其机理在哪？是糖中的桔水成分,或是红糖中的矿物质成分,值得研究。方法采用微波消解法处理样品,用电感耦合等离子体发射光谱法（ICP—AES）测定红糖中的微量元素。结果14种微量元素的检测限为1．1—7．3μg·L-1,方法准确度为96．7％-109．4％,方法精密度为0．88％-9．15％。结论微波消解样品快速、准确,用ICP—AES同时测定红糖中的镁、锌、铁、铜、铬、锰、钒、锶、镍、钴、硼、铅、镉和钛等14种微量元素,检出限低,适用于红糖微量元素的常规检测。     

The thermal properties of some metal complexes of diethyldithiocarbamic acid

The cobalt(II), cadmium(II), copper(II), mercury(II), nickel(II) and zinc(II) complexes of diethyldithiocarbamic acid were prepared and investigated by TG, DSC thin-layer chromatography and gas-liquid chromatography. Heats of fusion were determined.Permission to publish this paper has been given by the Government Chemist, Ministry of Technology.     

Simultaneous determination of traces of iron, cobalt, nickel, copper, mercury and lead in water by energy-dispersive x-ray fluorescence spectrometry after preconcentration as their piperazino-1,4-bis(dithiocarbamate) complexes

A bidentate chelating agent has been proposed to preconcentrate seven metal ions dissolved in an aqueous sample for their simultaneous determination using energy-dispersive x-ray fluorescence spectrometry. The metal ions are precipitated as their polymeric piperazino-1,4-bis(dithiocarbamate) chelates, which are then collected by vacuum filtration on a Millipore membrane filter for direct examination by x-ray fluorescence analysis. Iron, cobalt, nickel, copper and zinc are determined by means of their K x-rays and mercury and lead by means of their L x-rays. A detection limit in the μg1⁻¹ range can be achieved for all metals tested in 250-ml water samples with a counting time of 600 s. Effective precipitation of all metals occurs at pH 6–7. The recoveries of eight analyses of the metals in a multielement standard using the proposed method ranged from 97 to 105% and the precision ranged from 2.3 to 3.1%. High concentrations of calcium and magnesium do not interfere with the method. The method is simple, sensitive and accurate, and has been used for the simultaneous determination of the seven metals under study in environmental samples and synthetic mixtures.     

Test Determination of Cu(II), Ni(II), and Cr(VI) in a Single Sample

It was shown that Cr(VI), Ni(II), and Cu(II) can be simultaneously adsorbed on a solid phase consisting of two filled fibrous disks and then determined visually using organic reagents. One sorbent disk, a fibrous material filled with an AB-17 anion exchanger, was used to determine chromium by its reaction with 1,5-diphenylcarbazide. Another disk filled with an KU-2 cation exchanger was used for the simultaneous sorption of copper and nickel followed by the consecutive determination of nickel with dimethylglyoxime and copper with sodium diethyldithiocarbamate. The conditions were optimized for the determination of nickel in the presence of copper and of copper in the presence of nickel after decomposing its dimethylglyoxime complex with 1 M HCl. The detection limits were 0.02, 0.1, and 0.05 mg/L for Cr, Ni, and Cu, respectively. The time of analysis was no longer that 20 min.