Comparative substoichiometric extraction of silver with potassium salts of ethyl, propyl, butyl, pentyl and benzyl xanthates

A rapid and sensitive substoichiometric radiochemical method has been developed for the comparative extraction and quantification of silver with potassium salts of ethyl, propyl, butyl, pentyl and benzyl xanthates from hydrochloric, nitric and sulfuric acid media into chloroform. The effect of 0.1–4M H⁺ ion concentration of the respective acid on the substoichiometric extraction of silver was critically studied. The efficiency of the method developed was tested by the determination of 10–100 g silver in standard solutions with an average percentage of error better than 2. The methods developed have been utilized to determine silver content in photofilm washing collected from various photostudios in Tirupati, India.     

Substoichiometric radiochemical determination of silver with potassium ethyl xanthate in photofilm washings

An accurate and rapid radiochemical method has been developed for the determination of microgram amount of silver employing potassium ethyl xanthate as a substoichiometric radiochemical reagent. The light yellow coloured silver ethyl xanthate formed was extracted into nitrobenzene from sulphuric acid media. The effect of foreign ions on the extraction was studied. The method was applied to the determination of silver content in photofilm washings.     

Potassium 3-phenylmethyldithiocarbazate as substoichiometric reagent: Determination of silver

An accurate and rapid radiochemical method has been developed for the determination of silver based on the substoichiometric extraction of its complex with potassium 3-phenylmethyldithiocarbazate into chloroform from pH 5.5 acetate buffer. Microgram amounts of silver could be determined with an average error of ±1.1% and the effect of diverse metal ions was critically examined. The method developed was applied to evaluate the silver content of photofilm washings.     

Substoichiometry for multielement separation by metal chelate extraction and its application in activation analysis

The method of substoichiometric separation is completed for radioactivity measurements using special nuclear measurement methods in a way that along with the substoichiometric extraction of a given metal the simultaneous quantitative separation of other metals can also be effected. Some general relationships have been derived for the substoichiometric multielement separation of MA _m -type metal chelates. Particularly, the primary dithizonates of silver and copper(II) have been studied, and the application of the method is demonstrated by the separation of silver and copper from cobalt.     

Solvent extraction of Co/III/ with 1, 2, 3-benzotriazole into n-butanol

A new and rapid method has been developed for the quantitative extraction of Co/III/ with 1, 2, 3-benzotriazole into n-butanol. The extraction coefficient value of Co/III/ between n-butanol and an aqueous 5% solution of 1, 2, 3-BT in 2M sodium acetate-acetic acid buffer showed a maximum value of E=280 at pH 8.5. The effect of various other parameters on the extraction coefficient of Co/III/ such as solvents, anions, cations etc. has also been studied. The stoichiometry of the metal: reagent determined by the method of substoichiometric extraction and slope-ratio method was found to be 12. The separation factors studied for most of the elements were found to be better than 10³.     

Radiochemical determination of antimony

A radioanalytical method based on substoichiometric principles has been developed for the extraction and determination of antimony/III/ with 1-/2-pyridylazo/-2-naphthol /PAN/. Antimony/III/ forms a red complex with PAN in the presence of I^– or Br^–, which is extractable into benzene from sulphuric acid media.     

Determination of iodine in biological materials by neutron activation analysis

A method of determination of iodine (total and PBI) in serum, urine and other biological materials has been developed. The method consists in a gamma-spectrometric measurement of¹²⁸I activity after its radiochemical separation. The radiochemical separation procedure includes wet decomposition of the samples in a nitric acid medium followed by a few separation steps, the essential step being the substoichiometric extraction of iodide with a chloroform solution of tetraphenylarsonium chloride. Owing to the application of the substoichiometric separation, a high radiochemical purity of the separated iodine is achieved and the determination of the yield of radiochemical separation is not necessary.     

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.     

Substoichiometric determination of zinc by the isotope-dilution method using a chelating agent-loaded resin

A substoichiometric method for the determination of zinc has been developed. Zinc can be separated from other cations by using an anion-exchanger loaded with a substoichiometric amount of 8-quinolinol-5-sulphonic acid. Interfering metals can be removed beforehand by dithizone extraction. The feasibility of this method for water analysis was also examined.     

A study on the solvent extraction of Se/IV/ with 2-mercaptobenzothiazole into chloroform

The extraction of Se/IV/ from hydrochloric acid medium with 2-mercaptobenzothiazole/2-HMBT/into chloroform has been studied. The effect of various parameters on the extraction coefficient value such as molarity of hydrochloric acid, time of equilibration, effect of cations and anions etc., has been evaluated. The stoichiometry of the extracted species was determined by the method of substoichiometric extraction and slope ratio method and was found to be 1∶4. Decontamination factors for many elements in the substoichiometric extraction of Se/IV/ was also obtained.     

Substoichiometric radiochemical determination of antimony with potassium ethyl xanthate

A rapid and sensitive substoichiometric radiochemical method has been developed for the determination of microgram amounts of antimony employing potassium ethylxanthate as a reagent and chloroform as an extractant from sulfuric acid medium. The effect of associated ions on the extraction was studied. The method developed was successfully applied to determine the antimony content in standard solutions and synthetic mixture with an average error ±2.07%     

Substoichiometric determination of mercury with cetyltrimethylammonium bromide

A radiometric method based on substoichiometric isotope dilution analysis has been developed for the determination of mercury using cetyltrimethylammonium bromide (CTAB) as the substoichiometric reagent. The method is based on the extraction of mercury as an ionassociation complex of tetraiodomercurate(II) ion with a substoichiometric amount of CTAB in benzene. The calibration graph was found to be linear in the range 0–10 μg Hg (II) in the aqueous phase of 10 ml volume. A detection limit of 0.06 μg·ml⁻¹ could be achieved by the proposed method. The relative standard deviation of the method was found to be 3.0% and the method has been successfully applied to study the determination of mercury in various synthetic mixtures.     

Substoichiometric liquid-liquid extraction and determination of vanadium based on the synergic effect of thenolytrifluoroacetone and trioctylphosphine oxide

Vanadium(IV) is extracted synergically with thenoyltrifluoroacetone (HTTA) and trioctylphosphine oxide (TOPO) in cyclohexane as the mixed ligand complex, VO(TTA)₂TOPO. The synergic extraction constant is 10^5.06. The system can be used for the substoichiometric extraction of vanadium(IV); vanadium(IV) is extracted at pH 4.0–5.0 with a substoichiometric amount of HTTA in the presence of an excess of TOPO. The substoichiometric process combined with isotope dilution was successfully applied to the determination of vanadium(IV) in NBS-1633 coal fly ash; the value found was 222.5 ± 3.5 μg g^?1. The method is shown to be accurate and precise.     

Solvent extraction of Au(III) using 2-mercaptobenzimidazole into n-butanol

A method has been developed for the extraction of Au(III) with 2-mercaptobenzimidazole into n-butanol.¹⁹⁹Au has been used as a tracer for establishing the ideal extraction parameters such as effect of pH, time of equilibration, solvents and anions. Separation factor and decontamination factor have also been evaluated to determine the selectivity of the method with respect to various elements. The interfering elements were suppressed by the use of suitable masking agents which increased the selectivity. The stoichiometry of metal to reagent was determined by the method of substoichiometric extraction and slope ratio method.     

Determination of trace elements and radioactive materials by substoichiometric isotope dilution analysis

Substoichiometric isotope dilution analysis has been applied for the determination of trace elements in liquid samples, of carrier content in radioisotope solution and of concentration of organic reagent. Cu in mineral acids and in ZnSe single crystal was determined by the substoichiometric extraction with dithizone. The values of 1.8 and 0.018 ppm in nitric acid and distilled one and of 1.4 and 0.44 ppm in ZnSe were obtained. Cu and P carrier contents in⁶⁴Cu and³²P solutions were determined by the substoichiometric extractions with dithizone in CCl₄ and with molybdic acid into MIBK in the series of the solutions adding various amounts of Cu or P carrier. An analogous method has been applied for the determination of dithizone and diethyldithiocarbamate solutions. The method was also applied for the determination of⁶⁰Co radioactivity in environmental samples. The analytical result of water samples is described.     

Determination of lead in rocks by radiometric isotope dilution and substoichiometric extraction

A rapid procedure is described for the determination of lead in rocks by an isotope-dilution substoichiometric method. After the sample has been digested with acid in the presence of ²¹⁰Pb tracer, the lead is separated by dithizone extractions. After the lead has been back-extracted into aqueous solution, it is reacted with a substoichiometric amount of EDTA. Excess of unreacted lead is removed by extraction with dithizone in carbon tetrachloride, and the specific activity of the aqueous complex is determined by counting ²¹⁰Pb. The standard deviation of the method is less than 10 % for replicate determinations of lead in several U.S. Geological Survey standard rocks. The agreement with literature values indicates that the method is accurate.     

Substoichiometric isotope dilution analysis of calcium in biological materials

A substoichiometric isotope dilution analysis was developed for the determination of calcium in biological materials. A⁴⁷Ca tracer was produced by the photonuclear reaction and purified by a chromatographic technique on a zeolite column. The appropriate conditions and the reproducibility of the substoichiometric extraction system of TTA-TBP were examined. The present method was applied for NBS-SRM's Spinach and Pine needle, and very good results with high accuracy and precision were demonstrated.     

A new and rapid method for the solvent extraction of Ru/III/ with 1,2,3-benzotriazole into 1-pentanol

A new and rapid method has been developed for the quantitative extraction of Ru/III/ with 1,2,3-benzotriazole /1,2,3-BT/ into 1-pentanol. The extraction coefficient value of Ru/III/ between 1-pentanol and an aqueous 5% solution of 1,2,3-BT in 2M sodium acetate-acetic acid buffer showed a maximum value of E=46 at pH 4.5. The effect of various other parameters on the extraction coefficient of Ru/III/ such as solvents, anions, cations, etc. have also been studied. The stoichiometry of metal:reagent determined by the method of substoichiometric extraction and slope ratio method was found to be 13. Decontamination factors for many elements in the substoichiometric extraction of Ru/III/ were also evaluated.     

Determination of nickel,gold and silver in gallium arsenide by radioactivation analysis based on the quantitative isotope dilution principle

A method of radioactivation analysis has been developed for the determination of Ni, Au and Ag impurities in gallium arsenide. The separation and substoichiometric extraction of these elements were studied and analytical procedures are suggested for their determination. All components are separated by suitable procedures and determined by substoichiometric methods. Ni is extracted as diethyldithiocarbamate into toluene, Au as a complex of rhodamine-B in chloroform, and Ag as dithizonate in carbon tetrachloride. The contents of Ni, Au and Ag in a gallium arsenide crystal with a carrier concentration of 1.8·10¹⁶/cm³ were 0.05–0.08, 0.006–0.008 and 0.002–0.005 ppm, respectively.     

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.