Sine-wave polarographic determination of small amounts of indium in the presence of large amounts of cadmium,lead or tin

The sine-wave polarographic determination of small amounts of indium in the presence of large amounts of cadmium, lead or tin was investigated. The determination of indium in cadmium was possible down to 0.01 % in 1 M potassium iodide at pH 2, the determination of indium in lead was possible down to 0.02 % in 1 M potassium chloride at pH 2, and the determination of indium in tin was possible down to 0.3 % in 1 M hydrochloric acid and down to 0.2 % in 2 M perchloric acid with 0.5 M sodium chloride.     

Ion exchange separation in the analysis of bismuth base alloys : Part II. Ternary alloys containing uranium and thorium

Procedures are described for the analysis of bismuth base alloys containing uranium and thorium in the range from 0.1 to 10%. The thorium is first separated by the passage of a solution of the sample in 5M hydrochloric acid through a column of Deacidite FF in the chloride form. For thorium contents greater than about 1%, the determination is completed volumetrically with EDTA using pyrocatechol violet as the indicator. Smaller amounts are determined absorptiometrically by the thoronol method. Uranium is recovered from the ion-exchange column in a quantity of 0.2M hydrochloric acid, bismuth still being retained by the column under these conditions. Uranium contents greater than about 1% are determined volumetrically after reduction to the tetravalent state with a lead reductor, whilst smaller amounts are determined polarographically using a tartrate base solution.     

Solvent extraction separation of gallium with 18crown6 from chloride media

Gallium was quantitatively extracted with 0.02M 18crown6 in methylene chloride from 6M hydrochloric acid, then stripped with 1M acetic acid and determined with 2-(pyridylazo)naphthol with measurement at 545 nm. Gallium was separated from indium, thallium, lead, aluminium and bismuth. The method was applied to determination of gallium in bauxite.     

The extraction of copper(I), lead(II) and tin(IV) from hydrochloric acid by solutions of tetra-n-hexylammonium chloride in ethylene dichloride

Copper(I) is strongly extracted from chloride media as the ion-pair NR₄+CuCl₃-by solutions of tetra-n-hexylammonium chloride (NR₄+Cl-) in ethylene dichloride. The distribution coefficient decreases from ca. 100 in 1 M chloride but is still as high as 13 in 10 M chloride. The extraction of lead(II) is shown to be due to the partition of the ion-pair (NR₄+PbCI₃-). The percentage of 0.0018 M lead extracted is 98% from 0.58 M hydrochloric acid and falls to 38% from 7.8 M acid. The distribution coefficient decreases rapidly with the total lead concentration. The extractions of tin(IV) increased to a maximum of 99.5% in ca. 5 M hydrochloric acid but decreased rapidly above 6 M acid. It proved impossible to identify the extractable species.     

Direct determination of bismuth and antimony in sea water by anodic stripping voltammetry

A method based on anodic stripping voltammetry at the mercury-coated graphite electrode has been developed for the direct determination of bismuth and antimony at their natural levels in sea water. Bismuth plated at -0.4 V from sea water made 1 M in hydrochloric acid gives a stripping peak proportional to concentration at -0.2 V without interference from antimony or other metals normally present. Antimony may be plated from sea water made 4 M in hydrochloric acid and gives a stripping peak at -0.2 V proportional to the sum of bismuth and antimony. By use of the standard addition technique, satisfactory results were obtained for sea water samples with concentration ranges of 0.02–0.09 μg kg^?1 for bismuth and 0.2–0.5 μg kg^?1 for antimony.     

Analysis of lead titanate-zirconate ceramics: Determination of lead,titanium and niobium by differential cathode-ray polarography

Differential cathode-ray polarography is applied to the direct determination of lead, titanium and niobium in lead titanate-zirconate solid-solution ceramics containing small additions of niobium pentoxide. Titanium and niobium are determined in buffered EDTA solution at pH 4.0 and lead in 1 M hydrochloric acid. With the high precision comparative technique, relative standard deviations of 0.11% and 0.31% for lead and titanium respectively are obtained. Niobium is determined by the subtractive technique.     

The extraction of lead iodide by methyl iso-propyl ketone

A method is proposed for the isolation of lead by solvent extraction. When solutions of lead ions are treated with excess potassium iodide and hydrochloric acid (5 %), lead iodide is extracted quantitatively by methyl iso-propyl ketone. Employing a preliminary extraction with methyl iso-propyl ketone after conditioning the aqueous solution with ammonium thiocyanate and hydrochloric acid, practically all interferences are eliminated (except Cd and Ru).     

The extraction of niobium (V) and Tantalum (V) by Octylarsinic acid in chloroform

Dioctylarsinic acid (HDOAA) in chloroform solution extracts Nb(V) and Ta(V) efficiently from solutions containing oxalate and oxalic acid at hydrochloric acid concentrations greater than 1M.The extraction coefficients are 92.5 at 7M hydrochloric acid and 251 at 6M hydrochloric acid for niobium and tantalum, respectively. These metals can be extracted even more efficiently from sulfuric acid solutions. The results of the reagent- and pH-dependence studies suggested that a trimeric, monobasic oxoacid of niobium, associated with ten HDOAA molecules, is extracted. Tantalum appears to be present in the organic phase as (H₂DOAA)⁺ [Ta(C₂O₄)₃ (HDOAA_n] (n=l or 2).     

Polarographic determination of traces of zinc in bismuth after preconcentration by solid-liquid extraction

Summary Microgram or Nanogram quantities of zinc are extracted from solid basic bismuth nitrate with 0.07M phosphoric acid –0.12M hydrochloric acid for square-wave polarography. ppm of zinc in high-purity bismuth and bismuth nitrate is determined with excellent precision within 2 to 2.5 hours.

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Zusammenfassung Mikrogramm-oder Nanogramm-Mengen Zink werden aus festem basischem Wismutnitrat mit einer Mischung aus 0,07-m Phosphorsäure und 0,12-m Salzsäure extrahiert und durch Rechteckstufen-Polarographie bestimmt. In hochgereinigtem Wismut und Wismutnitrat lassen sich ppm Zn innerhalb 2 bis 21/2 Stunden mit hervorragender Genauigkeit bestimmen.

     

Reversed phase partition chromatographic separation of antimony (III) with bis(2-ethylhexyl) phosphoric acid

A new method is proposed for the extractive Chromatographic separation of antimony. Antimony is extracted from 0.001–0.5M hydrochloric acid by a silica gel column coated with bis (2-ethylhexyl) phosphoric acid stripped with 2–8M hydrochloric, nitric or sulphuric acid, and determined spectrophotometrically at 555 nm as its complex with phenylfluorone. Antimony can thus be separated from a large number of elements, including iron, manganese, copper and thallium. Arsenic, antimony, bismuth and tin can be sequentially separated.     

Selective spectrophotometric determination of uranium

Uranium(VI) (10–100 μg) is extracted with 2% dibenzoylmethane in benzene at pH 6–7 while other cations are masked with CDTA (maximum of 8 μg/100 ml). Shaking with 6 M hydrochloric acid reintroduces uranium(VI) into the aqueous phase, where after evaporation and complexation with Arsenazo III in 0.02 M hydrochloric acid the final measurement of absorbance at 650 nm is performed. Iron(III), copper(II), aluminum, and zinc do not interfere even if present in amounts of 15–19 mmol.     

Determination of seven trace elements in natural waters after separation by solvent extraction and anion-exchange chromatography

A method is described for the determination of cadmium, cobalt, copper, manganese, lead, uranium, and zinc in samples of natural waters. After acidification with hydrochloric acid the water sample is filtered and the diethyldithiocarbamates of the trace elements are isolated by extraction with acetone—chloroform (2:5) at pH 5. Following this preconcentration step the metal ions are adsorbed on a column of the strongly basic anion-exchange resin Dowex 1-X8 (chloride form) using as sorption solution a mixture (5:4:1, $\text{v}\text{v}$) of tetrahydrofuran, methyl glycol and 6 M hydrochloric acid. Successive elution is effected with 6 M hydrochloric acid (Co, Cu, Mn and Pb), 1 M hydrochloric acid (U) and 2 M nitric acid (Cd and Zn); the metal ions in the eluates are determined by atomic absorption spectrophotometry (except uranium, which is determined fluorimetrically). The procedure was used to determine the trace-metals in water and snow samples collected in Austria and to analyse a sample of sea water from the Adriatic Sea.     

Separation of large amounts of iron(III) from cobalt,nickel, and aliminum by combined ion exchange-solvent extraction

A method is described for the cation-exchange separation of large amounts of iron(III) from cobalt, nickel, and aluminium. On the strongly acidic Dowex 50-X8, iron(III) is not adsorbed from an 80% tetrahydrofuran-20% 3 M hydrochloric acid mixture, while cobalt, nickel, and aluminium are retained; a quantitative separation is thus possible. Cobalt and nickel or aluminium are then separated by elution with 90% tetrahydrofuran-10% 6 M hydrochloric acid. In these mixtures combined ion exchange-solvent extraction appears to occur; both ion exchange and liquid-liquid extraction are. effective simultaneously.     

Extraction-spectrophotometric determination of traces of bismuth in lead,copper and nickel metals,and in copper-base alloys with tri-n-octylamine

A rapid and sensitive spectrophotometric method has been developed for the determination of bismuth in lead, copper and nickel metals, and in copper-base alloys. Optimal conditions have been established for the extraction and determination of bismuth. Bismuth is extracted with a benzene solution of tri-n-octylamine in the presence of hydrobromic acid and the absorbance of the extract (bromo-complex of bismuth) at 380 nm is measured. As little as 0.5 p.p.m. of bismuth in these metals and alloys can be determined.     

ISolement du groupe des terres rares de l'apatite par l'acide di-(2-ethyhexyl)phosphorique (hdehp)

The liquid-liquid extraction of rare-earth elements (REE) by 0.75 M di-(2-ethylhexyl) phosphoric acid (HDEHP) in cyclohexane from perchloric acid (1–12M) has been investigated. At moderate perchloric acid molarities (1–6 M), the distribution coefficient, E, has an inverse third-power dependency upon the acid concentration in the aqueous phase. However, at higher perchloric acid concentrations, the slope of the resulting curve is about +18, which means a change in the extraction mechanism. In 12 M perchloric acid medium, REE are quantitatively and selectively extracted from apatite minerals, in the organic phase. In order to strip out all the lanthanides, back-extractions were carried out with 9 M hydrochloric acid solutions.     

Extraction,Separation and Spectrophotometric Determination of Bismuth(III) Using 1(4′-Bromophenyl) 4,4,6-Trimethyl (1H,4H)-Pyrimidine-2-Thiol

Abstract

The operating conditions for the spectrophotometric determination of bismuth(III) with 1-(4′-bromophenyl)-4,4,6-trimethyl-(1H,4H)-pyrimidine-2-thiol (4′bromo PTPT) as a ligand by a liquid-liquid extraction technique are presented. In acidic conditions bismuth(III) forms a yellow complex with the ligand which can be extracted in chloroform with an absorption maxima at 410 nm. The molar absorptivity is 1.5×10⁴ l mole^?1 cm^?1 and Sandell's sensitivity is 14.3 ng cm^?2. The difference in the absorbance between the chloroform blank and bismuth(III) sample increases linearly in the concentration range 2-14 ppm at 0.3 M hydrochloric acid. The proposed method is extremely sensitive, rapid, reproducible and has been satisfactorily applied to the determination of trace amounts of bismuth(III) in synthetic mixtures, alloys and pharmaceutical formulations and also provides binary separation of bismuth(III) from selenium, tellurium, lead, antimony, copper and gold. The overall process of extraction and determination takes about 15 to 20 min.     

Simultaneous determination of tin and lead by anodic stripping voltammetry in aqueous-alcoholic medium. Application to the direct determination of these elements in canned foods

Tin and lead may be determined in mixture in a solution of 50% methanol-50% isopropanol containing l M hydrochloric acid. The solvent-electrolyte composition affects both the relative a.s.v. peak heights and peak resolution. Iron(III) in large quantities does not interfere, and mixtures of copper, lead, tin, and cadmium may be analyzed. Juice samples can be analyzed without digestion, by simple 1:5000 dilution (5 μl to 25 ml) with the above solvent electrolyte. It was demonstrated that tin gradually dissolves from cans containing the juice.     

Determination of cadmium, copper and lead in natural waters after anion-exchange separtion.

A method is described for the determination of cadmium, copper and lead in samples of natural non-saline waters. After acidification with hydrobromic acid, the water sample is filtered and, following the addition of ascorbic acid, passed through a column of the strongly basic anion-exchange resin Dowex 1-X8 (bromide form). On this exchanger cadmium(II). copper(I) and lead(II) are adsorbed as anionic bromide complexes. After elution of these elements with 1 M nitric acid, the determinations by atomic absorption spectrometry are carried out in a medium consisting of 90% ($\text{v}\text{v}$) methanol and 10% ($\text{v}\text{v}$) 1.5 M hydrobromic acid. The procedure was used for the routine determination of cadmium, copper and lead in water samples collected in Austria.     

Anwendung von ionenaustauschverfahren zur bestimmung von spurenelementen in natürlichen wässern—V: Blei

A method is described which makes possible the separation of lead from natural waters at the ppM level, and its final determination by spectrophotometry or atomic absorption. The sample is made 0.15M in hydrobromic acid, filtered, and passed through Dowex 1 X8 (bromide form). The lead is sorbed on the resin and most of the other elements present are separated from it. The lead is eluted with 6M hydrochloric acid and determined by the dithizone method or by atomic-absorption. The method was used to determine lead in drinking water and water from the Danube, lead concentrations in the range 2–14 ppM being found.     

A simple separation of bismuth radionuclides in a carrier-free form from lead thick targets

A simple preparation of radionuclides of bismuth from lead thick targets bombarded by deuterons or protons consists in precipitation of solid lead nitrate in nitric acid /a minimum radiobismuth yield 98%/, coprecipitation of bismuth with lanthanum hydroxide and chromatographic isolation of carrier-free bismuth on a cation exchanger. The total yield of radiobismuth separation was not less than 85%. On bombardment with 20 MeV deuterons the yield is 20 Ci²⁰⁵Bi/Ah and 200 Ci²⁰⁶Bi/Ah. Mass distribution coefficients for bismuth were determined on the cation exchanger OSTION LG KS 0803 in dependence on the concentration of hydrochloric acid and nitric acid.