Substoichiometric determination of manganese by neutron-activation analysis

A simple and rapid method for the substoichiometric determination of traces of manganese in various materials by neutron-activation analysis has been developed. After dissolution of the irradiated test sample, manganese(II) carrier is added and subsequently oxidised by peroxodisulphate to the heptavalent state. The permanganate thus formed is finally extracted into chloroform as tetraphenylarsonium permanganate using a substoichiometric amount of tetraphenylarsonium chloride. This single separation step isolates radiochemically pure manganese-56 in the analysis of a relatively simple material in which interfering elements (gold, rhenium, etc.) are absent. When this is not true, a preliminary separation of manganese from the irradiated sample, based on the extraction of manganese diethyldithio-carbamate into chloroform and followed by stripping of the manganese with dilute sulphuric acid, must be used. A simultaneously irradiated standard containing manganese must be treated in exactly the same way as a test sample. In the materials analysed by the new method 10(-5) to 10(-3)% of manganese has been determined.     

Substoichiometric radioactivation analysis for ytterbium

The substoichiometric separation of Yb(III) can be achieved by the extraction of a substoichiometric amount of thenoyltrifluoroacetone and an excess amount of phenanthroline in benzene. The appropriate pH range for the substoichiometric extraction is 6–8. The reproducibility of the substoichiometric extraction of Yb(III) is very good as RSD 1%. As an example, Yb in a manganese nodule is determined by the substoichiometry combined with the radioactivation analysis. The content of Yb is 17.63±0.23 g/g. The present procedure can be applied to the determination of other rare earth elements.     

Substoichiometric separation in activation analysis: extraction of co-ordinatively-unsolvated salts

The necessary conditions have been examined for the use of extraction of coordinatively-unsolvated salts for substoichiometric separations in activation analysis, especially the influence of interfering ions and of the concentration of the carrier. A study has been made of the substoichiometric extraction of halide ions, oxyanions and anionic metal complexes by means of the tetraphenylarsonium ion into chloroform and dichloroethane, and of the extraction of alkali metal ions into nitrobenzene with tetraphenylborate. Substoichiometric extraction can be combined with neutron-activation analysis for the determination of traces of iodine, caesium, rubidium, manganese, rhenium, chromium, thallium, gold, gallium and tantalum.     

Sorption of cobalt on modified clinoptilolites

A method of radioactivation analysis has been developed for the substoichiometric determination of cobalt, copper and manganese in glass and glass-making materials. The substoichiometric extraction of cobalt with α-nitroso-β-naphthol was studied and simple procedures are suggested for the determination of the three elements. Cobalt is extracted substoichiometrically as α-nitroso-β-naphtholate into chloroform from solution of pH 6.2, copper as dithizonate in carbon tetrachloride from weak acidic solution, and manganese as tetraphenylarsonium permanganate into chloroform after oxidation to permanganate. Contents from 2 ppm to 3 ppb of cobalt, copper and managanese were analysed in glass-making materials, and it is shown that the method for their determination is reliable and superior in accuracy and reproducibility.     

Determination of cadmium by substoichiometric thermal neutron activation analysis

A rapid and selective method has been developed for the determination of cadmium in environmental samples by thermal neutron activation analysis, employing substoichiometric solvent extraction technique. Alcoholic solution of 2-mercaptobenzothiazole /2-HMBT/ has been used for the substoichiometric extraction of Cd/II/ from an aqueous solution of pH 7.0 into methyl iso-butyl ketone /MIBK/.     

A new principle of activation-analysis separations-X Substoichiometric determination of traces of gallium

A rapid method for the substoichiometric determination of gallium by neutron-activation analysis has been developed. After irradiation and dissolution of the test sample, gallium carrier is added and two preliminary separation steps are performed: the extraction into chloroform of cupferrates from 7N sulphuric acid and of diethyldithiocarbamates from 2-3N sulphuric acid. The pH of the remaining aqueous phase is then adjusted to 5.5, the solution extracted with a substoichiometric amount of 8-hydroxyquinoline in chloroform and the activity of the gallium hydroxyquinolate extract measured. A simultaneously irradiated gallium standard is treated in exactly the same way. From the activities of these two substoichiometric extracts the amount of gallium originally present in the test sample can be calculated. The method has been applied to the determination of 10(-6) to 10(-3)% of gallium in metallic aluminium and transistor-grade silicon.     

Mutual separation of Co(II), Fe(III), Eu(III) and Tb(III) on HTTA-loaded polyurethane foam

The selectivity of the 2-thenoyltrifluoroacetone (HTTA) loaded polyurethane (PUR) foam as adsorbent was studied. The influence of various anions on the adsorption indicated that permanganate, oxalate, EDTA, and citrate formed strong complexes with the metal ions and masked completely, while phosphate, thiosulphate, cyanide, ascorbate, tartrate and fluoride hindered the sorption of Fe(III). The sorption of Co(II) is also prohibited in presence of anions like cyanide, ascorbate and tartrate. The sorption of Eu(III) and Tb(III) is greatly affected in the presence of phosphate and fluoride. A group separation of different metals has been proposed on the basis of selectivity of the foam.     

Substoichiometric precipitation of fluoride with lanthanum

The substoichiometric precipitation of fluoride with lanthanum was studied by using¹⁸F and¹⁴⁰La tracers and it was found that fluoride could be precipitated substoichiometrically with lanthanum and the reaction ratio between fluoride and lanthanum was 3∶1. The pH range at which fluoride can be separated substoichiometrically with lanthanum is between 2 and 8. Barium and indium interfere in the precipitation of fluoride, sodium, copper and manganese, however, not. Fluorosilicate can also be precipitated substoichiometrically by using lanthanum as a precipitant and the reaction ratio between fluorosilicate and lanthanum was 1∶2. This separation was applied for the determination of oxygen in silicon crystals. The concentration of oxygen measured in some silicon crystals was between 5 and 27 ppm and in good agreement with those by non-destructive method and infrared spectrophotometry.     

Substoichiometric determination of chromium by neutron activation analysis

A method of radioactivation analysis has been developed for the determination of chromium. It is based on the substoichiometric extraction of chromium diethyldithio-carbamate into methyl-isobutyl-ketone from acetate buffer solution in the presence of EDTA and potassium cyanide. The method has been applied for the determination of chromium in high-purity calcium carbonate and NBS glasses as standard reference materials.     

Substoichiometric determination of zinc with potassium ethyl xanthate

A rapid radiochemical method has been designed for the determination of microgram quantities of zinc, based on the substoichiometric isotope dilution, using potassium ethyl xanthate as the extraction reagent. pH 5.5 in acetate buffers and chloroform as the extractant were found to be suitable for quantitative substoichiometric extraction. The influence of the diverse ions on the extraction was studied. The zinc contents of a medicinal preparation and biological samples were determined by the present method.     

Solvent extraction of Os(IV) with 2-mercaptobenzothiazole into chloroform

2-mercaptobenzothiazole has been used for the solvent extraction of Os(IV) in acidic medium. The extraction of Os(IV) was found to be better than 90% over the pH range of 3.0 to 5.0 with an equilibration time of 5.0 minutes. The stoichiometry of metal:reagent determined by substoichiometric extraction and slope ratio method was found to be 1∶4. Decontamination factor for various elements in the substoichiometric extraction of Os(IV) were also evaluated.     

Spectrophotometric Determination of Manganese with 4(5)-Imidazolealdoxime (Imalox)

Abstract

A method is described for the spectrophotometric determination of manganese by means of its complex with 4(5)-imidazolealdoxime, IMALOX, formed in alkaline medium. The colour system has its absorption maximum at 350 nm and obeys Beer's law over the range 0.8–8.0 μg of Mn per ml. The optimum range is 1–5 μg m^?1. The molar absorptivity is 7850 1 mol^?1 cm^?1. Relatively few ions interfere, and these can be masked with cyanide, tartrate and NTA. The experimental results have been critically analyzed and a comparison with the main spectrophotometric reagents for manganese is presented.     

A study on the solvent extraction of Ag/I/ with 1,2,3-benzotriazole in chloroform

A rapid and selective method has been developed for the substoichiometric extraction of Ag/I/with 1,2,3-benzotriazole /1,2,3-BT/ in chloroform in the presence of versenate. The effect of various parameters such as pH, time of equilibration, solvent, anions, cations, etc., on the extraction coefficient value has been studied. The stoichiometry of the extracted species of 11 /Ag:1,2, 3-BT/ was obtained by the slope ratio method and substoichiometric extraction. Decontamination factors for most elements in the substoichiometric extraction of Ag/I/ were found to be higher than 10⁴.     

Extraction spectrophotometric method for determination of aluminium in silicates

A simple, rapid and sensitive method has been worked out for spectrophotometric determination of macro and micro amounts of alumina in ceramic raw materials and finished products, including glasses. The method is based on the extraction of aluminum oxinate into chloroform after masking of titanium with chromotropic acid and of iron with ascorbic acid and 1,10-phenanthroline or ferrocyanide at pH 5.2. The absorbance is measured at 385 nm. Interference by Cu, Zn, Cd, Ni and Co, when present, is overcome by stripping them as cyanide complexes by shaking the chloroform extract with potassium cyanide solution. Zr is masked with quinalizarin sulphonic acid and fluoride with BeSO(4).     

Synergistic extraction of Ce(III), Eu(III) and Tm(III) with a mixture of picrolonic acid and benzo-15-crown-5 in chloroform

Summary The synergistic mixture comprising picrolonic acid (HPA) and benzo-15-crown-5 (B15C5) in chloroform has been used for the extraction of Ce(III), Eu(III) and Tm(III) as representatives of lanthanide(III) ions from pH 1-2 solutions having ionic strength of 0.1 mol^. dm^-3(K⁺/H⁺, Cl^-). The composition of the extracted species has been determined as M(PA)₃^. nB15C5 where M is Ce, Eu and Tm and n=1 or 2. The influence of various anions and cations on the extraction of these ions has also been studied and only oxalate, cyanide and tartrate have some deleterious effect. The extraction equilibrium constants have been evaluated and discussed.     

Studies on the adsorption behaviour of trace amounts of cerium on manganese dioxide from aqueous solutions in the presence of complexing agents

Adsorption behaviour of trace amounts of cerium on manganese dioxide has been studied as a function of pH (1–10) in the presence of EDTA, oxalate, citrate, tartrate, cyanide and thiocyanate ions. The influence of their concentration on the adsorption has also been investigated. Maximum adsorption of cerium has been noticed at pH6. Under specific conditions, adsorption of other metal ions has been measured for comparison. Low distribution coefficients are obtained for Cs(I) and Hg(II) in the presence of oxalate, and for Cr(III) in the presence of thiocyanate ions. Based on these data, separation of cesium, chromium and mercury from rare earths and cerium scavenging in natural water or in waste water treatment can be achieved.     

Solvent extraction of Ni/II/ with isonitrosobenzoylacetone into chloroform

A method has been developed for the quantitative extraction of Ni/II/ with isonitrosobenzoylacetone /HINBA/ into chloroform. The effect of various parameters on the extraction coefficient value such as pH, time of equilibration, effect of solvents, anions, cations etc. have been studied. The stoichiometry of the metal: reagent determined by the method of substoichiometric extraction and slope ratio method was found to be 12. Decontamination factors for many elements in the substoichiometric extraction of Ni/II/ were also evaluated.     

Solvent extraction of Ru(III) with 2-mercaptobenzimidazole into n-butanol

A new and rapid method has been developed for the quantitative extraction of Ru(III) with 2-mercaptobenzimidazole into n-butanol. The extraction coefficient of Ru(III) between n-butanol and an ethanolic solution of 1% 2-mercaptobenzimidazole showed a maximum value ofE=161 at a pH of 2.0. The effect of various other parameters on the extraction coefficient value of Ru(III) such as solvent effect, anions, cations, etc. have also been studied. The stoichiometry of metal to reagent has also been determined by the method of substoichiometric extraction and by the slope ratio method and was found to be 1∶3. Decontamination factor for various elements in the substoichiometric extraction of Ru(III) were also evaluated.     

Solvent extraction of W(VI) with rhodamine-B in nitrobenzene

A rapid and selective method has been developed for the extraction of W(VI) with rhodamine-B in nitrobenzene. The extraction coefficient value for the extraction between aqueous solution and nitrobenzene showed a maximum value of E=63 at a pH of 5.0. The stoichiometry of metal to reagent has been determined by the method of substoichiometric extraction and slope ratio method.     

Trace level determination of manganese in liver tissues employing substoichiometric thermal neutron activation analysis

Liver tissues from rat have been analyzed for determining trace amounts of manganese present by employing thermal neutron activation analysis and substoichiometric solvent extraction of Mn/II/ with 1,2,3-benzotriazole into 1-octanol. Three samples and a standard can be processed and counted within three hours.