Electro-chromatography in the separation of ions : Part III. Separation of silver group metals

The migration sequences of silver group ions Ag⁺, Hg₂⁺², Pb⁺²and Ti⁺ have been studied in a number of complex-forming electrolytes. Based on the migration sequences, the ions in a mixture can be separated into distinct zones using a decinormal solution of sodium chloride, potassium chloride or potassium cyanide as the electrolyte. The sequence is Hg — Ag— Pb—Ti, while in KCN at pH 7.0 the sequence becomes Ag—Hg—Pb—Ti.     

Internal electrolysis for the separation of ions: Microdetermination and separation of nickel and cobalt

Summary The application of internal electrolysis with the Pt-Zn electrode assembly has been described for the separation and determination of nickel and, cobalt (in the 1–5 mg range) from each other and from other ions as well as the determinations of bismuth, copper, cadmium, lead, antimony, nickel and cobalt when present in a mixture.

---

Zusammenfassung Die Anwendung der internen Elektrolyse mit einer Pt-Zn-Elektrodenanordnung für die Trennung und Bestimmung von Nickel und Kobalt (in der Größenordnung 1 bis 5 mg) nebeneinander und in Gegenwart anderer Ionen wird beschrieben. Desgleichen auch die Bestimmung von Bi, Cu, Cd, Pb, Sb, Ni und Co in einer Mischung.

     

Paper chromatography in the separation of ions : Separation of silver,copper and arsenic group elements

A paper Chromatographic study ot the separability of ions of elements of the silver, copper and arsenic groups, using different solvents and a number of complexing agents, reveals that the solvents consisting of (1) acetone, hydrochloric or acetic acid (with or without ammonium iodide) and (2) tert. -butyl alcohol, hydrochloric or acetic acid, promote the complete separation of at ; least five elements present in microgram amounts in a mixture. Other complexing agents, such as thiourea, bismuthiol I, bismuthiol II and 2-mercaptobenzothiazole are not very useful in the separation of the ions. The R_I., R_T values and the sequences of separation are tabulated to show their behaviour.     

Electro-chromatography in the separation of ions : Part II. Separation of precious metals

An electrochromatographic study of the migration rates and sequences of the precious metals, as Pt⁺⁴, Os⁺⁴, Ir⁺⁴, Ru⁺³, Rh⁺³, Au⁺³ and Pd⁺², on paper strips, reveals that quite a large number of electrolytes effectively separate in distinct zones at least four ions present in microgram amounts in a mixture, when the voltage is maintained at 150 V for 5 hours.     

Iodometric determination of ferricyan in the presence of copper,silver, cadmium and zinc

Ferricyan can be determined in the presence of copper, silver and cadmium by addition of potassium ferrocyanide, filtration of the ferrocyanides of copper, silver and cadmium formed in this reaction, and titration of the potassium ferricyanide contained in the filtrate. In the case of silver, the ferricyan can also be determined without filtration by addition of potassium iodide and titration of the ferricyanide. In the case of zinc, potassium, ferrocyanide is added and without filtration the ferricyanide titrated.     

Electro-chromatography in the separation of ions : Separation of copper and tin group metals

The ionic migration and hence the migration sequences of the ions of the copper and the tin groups have been determined in a number of common electrolytes which act as complexing agents. Separation of several three,- four- and five-coniponent mixtures of copper group elements has been effected. Of the electrolytes, hydrochloric acid, sodium chloride and potassium chloride, the last gives the best and most complete separation of all the copper group ions from a mixture, a potential of 150 V being maintained for 5 h. The metals of the tin group cannot be separated completely from each other under the experimental conditions, only separation from binary mixtures is possbble.     

Separations involving palladium: Separation of lead,bismuth, cadmium,thallium, copper,cobalt and nickel from palladium

It has been shown that 1% dimethylglyoxime solution in alcohol can be efficiently used to separate quantitatively palladium from other metals of the copper group, as indicated in the new and more comprehensive scheme of qualitative analysis.     

Potentiometric determination of tetraphenylborate ions with silver nitrate. Determination of silver, potassium and thallium(I)

Summary The potentiometric determination of tetraphenylborate with silver nitrate solution was investigated a) at i=0 in the presence of calomel reference electrode and silver resp. silicone rubber based halide-selective indicator electrodes and b) at i0 in the presence of silver (cathode)-calomel, silver-silver, silver-platinum, platinum-silver and graphite-silver electrode couples. An indirect method is described for the determination of potassium ions with potentiometric end-point indication. Experiments were also carried out in order to develop methods for the titration of silver, potassium and thallium(I) ions with sodium tetraphenylborate solution in the presence of anodic polarized graphite and calomel reference electrodes. The relative standard deviations were 0.38–0.49% for tetraphenylborate, 1.96% for potassium and 1.07% for thallium(I).

---

Potentiometrische Bestimmung von Tetraphenylborationen mit Silbernitrat. Bestimmung von Silber, Kalium und Thallium(I)

Zusammenfassung Die Möglichkeit der potentiometrischen Bestimmung von Tetraphenylborat mit Silbernitrat wurde untersucht a) in Anwesenheit von Kalomel-Bezugselektrode und Silber- bzw. haloidselektiven Silicongummi-Indicatorelektroden bei i=0 und b) in Anwesenheit von Silber (Kathode)-Kalomel-, Silber-Silber, Silber-Platin-, Platin-Silber- und Graphit-Silber-Elektrodenpaaren bei i0. Eine Methode zur indirekten potentiometrischen Bestimmung von Kalium sowie Verfahren zur Bestimmung von Silber-, Kalium- und Thallium(I)-ionen mit Natriumtetraphenylboratlösung in Anwesenheit einer anodisch polarisierten Graphitelektrode und einer Kalomel-Referenzelektrode wurden ausgearbeitet. Die relativen Standardabweichungen betragen für Tetraphenylborat 0,38–0,49%, für Kalium und Thallium 1,96 bzw. 1,07%.

     

Atomic-absorption spectrometric determination of silver,bismuth and cadmium in sulfide ores by direct atomization from the solid state

Atomic absorption spectrometric determinations of silver, bismuth and cadmium in the Canadian SU-1 and the Nordic ASK reference sulfide ores and in a series of Norwegian sulfide ores of technical importance, were carried out by atomizing the elements directly from the solid state. Atomizations were made in a high-frequency induction-heated graphite furnace. For comparison purposes, samples were also decomposed, and analyses made by atomizing sample solutions in the furnace and in the flame.     

Reduction and aggregation of silver,copper and cadmium ions in aqueous solutions of gelatin and carboxymethyl cellulose

Radiolytic reduction of silver, copper and cadmium ions and the subsequent formation of their clusters was studied in aqueous gelatin or carboxy methyl cellulose (CMC) solutions. Presence of gelatin or CMC in the solution affects the early processes. The rate of reduction by hydrated electron reduces due to complexation. However, when the ratio of silver ions to monomeric chains decreases over a certain limit the process of reduction inhibits completely. The effect of ionic strength or pH and the reducing radical on the rate of formation of colloidal Cu and Cd is also discussed.     

The determination of copper ions based on sensitized chemiluminescence of silver nanoclusters

We report on the first application of novel, water-soluble and fluorescent silver nanoclusters (Ag NCs) in a chemiluminescent (CL) detection system. A method has been developed for the determination of copper(II) ion that is based on the fact that the weak CL resulting from the redox reaction between Ce(IV) ion and sulfite ion is strongly enhanced by the Ag NCs and that the main CL signals now originate from Ag NCs. UV-visible spectra, CL spectra and fluorescent (FL) spectra were acquired to investigate the enhanced CL mechanism. It is proposed that the electronic energy of the excited state intermediate SO₂* that originates from the CL reaction is transferred to Ag NCs to form an electronically excited NC whose emission is observed. In addition, it is found that copper(II) is capable of inhibiting the CL of the nanoclusters system, but not if other common metal ions are present. The detection of copper(II) is achieved indirectly by measuring the CL intensity of Ag NCs. Under the optimized experimental conditions, a linear relationship does exist between the intensity of CL and the concentrations of copper(II) in the range of 0.2?nM to 0.1?m??. The detection limit is 0.12?nM. The method is applied to the determination of copper(II) ion in tap water with satisfactory results.

Highly sensitive fluorescence determination of silver ions based on functionalized cadmium telluride nanorods

Microchimica Acta - Water-soluble fluorescent CdTe nanorods (NRs) capped with L-cysteine (Cys) and thioglycolic acid (TGA) were prepared for optical determination of silver ions. These NRs are...     

Simultaneous spectrophotometric determination of cadmium, copper and zinc

A method for the simultaneous spectrophotometric determination of cadmium, copper and zinc based on the formation of their complexes with 1,5-bis(di-2-pyridylmethylene)thiocarbonohydrazide is proposed. The absorption curves of these complexes overlap severely in the scanning range 380–480 nm. The analyte concentrations are calculated by a least squares fit of the pure spectra to the mixture spectra. A linear determination range of 0.1–1.7 μg/ml for cadmium, 0.1–1.3 μg/ml for copper and 0.2–1.2 μg/ml for zinc were obtained. The effect of interference was studied. The method has been applied to the determination of these metal ions in various type of materials.     

Separation of silver from zinc, cadmium, copper, nickel and other elements in nitric acid with a macroporous resin

Traces of silver and amounts up to 50 mg can be separated from up to gram amounts of Zn, Cu(II), Ni, Co(II), Mg, Be, Ti(IV), V(IV), Li and Na by eluting these with 2.0M nitric acid from a column containing 54 ml (20 g) of macroporous AG MP-50 cation-exchange resin of 100-200 mesh particle size, in the H(+)-form. Silver is retained and can be eluted with 0.5M hydrobromic acid in 9:1 v v acetone-water. Separations are sharp and quantitative and only a few microg of the other elements are found in the silver fraction. Cadmium and manganese (II) can also be separated quantitatively but show tailing and require larger elution volumes. Some typical elution curves and results of analyses of synthetic mixtures are presented.     

Submicro determination of aluminium, bismuth and copper in organometallic compounds

Methods for the determination of aluminium, bismuth or copper m samples of organometallic compounds weighing 40-110 microg have been developed. Spectrophotometric determination following digestion with nitric and sulphuric acids in a sealed tube is recommended, all results obtained from the analysis of standard compounds being within +/- 0.3% absolute error. Digestion in an open tube with perchloric and sulphuric acids gives satisfactory results for bismuth compounds but erratic and often low results for aluminium and copper compounds.     

Product distribution in preparative scale electrolysis: Part I. Introduction

The purpose of the present series is to establish and discuss the relationships between the distribution of products in preparative scale electrolysis and characteristic rates or ratios and magnitude of the operational parameters for a set of reaction schemes that can be encountered in a large variety of electrochemical processes. This can help in optimizing the yield of the target product for a given electrosynthetic reaction by a proper choice of the reaction conditions. Furthermore, systematic analysis of the product distribution as a function of the various parameters may in many cases be the only route to the reaction mechanism due to the time-scale limitations of the standard electrochemical kinetic techniques. The reaction sequences thus considered involve, besids electron transfer at the electrode, fast accompanying chemical reactions and competing chemical or electrochemical follow-up reactions. Reaction intermediates are thus confined within a reaction layer the thickness of which is small as compared to that of the diffusion layer in the context of the Nernst approximation. The other basic assumptions and procedures of resolution of the mathematical models are defined and discussed. Three different electrolysis regimes are considered involving potentiostatic or galvanostatic control and continuous or discontinuous electrolysis operations. A first reaction scheme is analyzed within this context involving the competition between homogeneous and heterogeneous electron transfer after a first electron transfer followed by an irreversible chemical step. The preliminary resolution of this ECE-Disp problem is indeed required for a number of reaction mechanisms of more definite chemical interest.     

Direct flame atomic absorption spectrometric determination of bismuth,cadmium, cobalt,silver, palladium and zinc in pure platinum with pulse aspiration

The method involves pulse aspiration of samples in ethanolic 3 M hydrochloric acid solutions. The detection limits vary from 1×10^?5 to 2×10^?4%. The depressive effect of platinum is corrected mathematically, so that standard additions or matrix matching are unnecessary.