Substoichiometric determination of copper by neutron-activation analysis

A rapid and selective method has been developed for the determination of Cu in complex matrices by thermal neutron-activation analysis employing substoichiometric extraction with 1,2,3-benzotriazole /1,2,3-BT/ into chloroform. The time required for radiochemical purification and counting of two samples was 2 h. 1.015 g Cu can be determined with an accuracy of 6.40% and a purification of 5.26%.     

Substoichiometric determination of traces of palladium by neutron-activation analysis

A highly selective, rapid one-step radiochemical separation procedure for palladium has been developed. It is based on the solvent extraction of palladium diethyldithiocarbamate from a 5M hydrochloric acid solution with a substoichiometric amount of copper diethyldithiocarbamate in chloroform. The separation has been applied to the determination of traces of palladium by neutron-activation analysis, in platinum, the rocks W-1 and PCC-1 and a biological material (kale). Amounts of palladium down to 10(-8) g have been determined.     

Substoichiometric determination of traces of gold by neutron-activation analysis

A highly selective, rapid, one-step radiochemical separation procedure for gold has been developed. It is based on the solvent extraction of gold diethyldithiocarbamate from a 0.01–10N sulphuric or hydrochloric acid medium using a substoichiometric amount of copper diethyldithiocarbamate in chloroform. The separation has been applied to the determination of traces of gold by neutron-activation analysis in high-purity lead, the rock W-1, gold-doped semi-conductor-grade silicon and a biological material (kale). Amounts of gold down to 2 × 10⁻¹⁰ g have been determined.     

Substoichiometric determination of molybdenum in steels by neutron-activation analysis

A simple and rapid substoichiometric method for the determination of small amounts of molybdenum in steel by neutronactivation analysis is based on the extraction of molybdenum alpha-benzoinoximate into chloroform. The sensitivity of the method is 0.2 microg and the relative standard deviation is 1%. Two activated samples can be processed and counted within 30 min.     

Simultaneous determination of arsenic, manganese, and selenium in biological materials by neutron-activation analysis

A new method was developed for the simultaneous determination of arsenic, manganese, and selenium in biological material by thermal-neutron activation analysis. The use of (81 m)Se as indicator for selenium permitted a reduction of activation time to 1 hr for a 1 g sample, and the possibility of loss of volatile compounds during irradiation could be dismissed. No pretreatment of the sample is required, and the radiochemical separation scheme is based on simple chemical operations, completed in less than 3 hr. A systematic experimental investigation of the performance characteristics of the method was carried out, including studies of the accuracy of the results. The actual precision achieved in routine application of the method in the analytical laboratory was in good agreement with the calculated precision, and the results are therefore well suited for statistical evaluation of differences at the ppM level in samples of biological tissue.     

Substoichiometric determination of tungsten by neutron activation analysis

A method for the substoichiometric determination of tungsten by thermal neutron activation analysis has been developed based on the selective extraction of the tungsten dithiol complex into amyl acetate. The method is simple, rapid and accurate. It has been used in the determination of tungsten in alloy steel, meteorites and biological standard kale.     

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 mercury by neutron activation analysis

A method has been developed for the substoichiometric determination of mercury by thermal neutron activation analysis, based on the selective extraction of the Hg(II)—Bindschedler's Green complex into 1,2-dichloroethane. The method has been applied for the determination of trace amounts of mercury in geological standards such as W-1, GR, Sye-1, and T-1, meteorite Allende de Publito, and biological materials such as kale, IR1 standard tobacco, and human blood serum.     

Substoichiometric determination of palladium by neutron activation analysis

A method is described for the substoichiometric determination of traces of palladium by neutron activation analysis involving the extraction of palladium with isonitrosoacetophenone. The sensitivity of the method is 0.005 μg of Pd. With 200 mg of silver alloy containing 0.0005% palladium, the average of three determinations of Pd is 0.98 μg, which varies between 1.07 μg and 0.91 μg at 95% confidence limit. The time required for radiochemical purification and counting of the sample does not exceed 12 minutes. Part of this work was presented at the International Conference on Modern Trends Activation Analysis, held in Gaithersburg, Maryland, USA, October 7–11, 1968.     

Substoichiometric determination of Cd by neutron activation analysis

A rapid method has been developed for the determination of cadmium in environmental samples by thermal neutron activation analysis involving substoichiometric extraction with 1,2,3-benzotriazole /1,2,3-BT/. Cd was radiochemically separated as CdS using 1-amidino-2-thiourea. The time required for radiochemical purification containing two samples and a standard was about 2 h. 4.63 g of Cd can be determined with an accuracy of 6.69% and precision of 6.25%. Mash potatoes, animal bones, raw sludge and cattle manure have been analyzed by this method.     

Substoichiometric neutron-activation determination of gallium: extraction from HCl with tri-n-octylphosphine oxide in cyclohexane

A highly precise method for the determination of traces of gallium by neutron activation is described. Conditions for the extraction of gallium are reported and general requirements for substoichiometric isolation of cations from HCl with neutral donors are discussed. The mean of determinations of gallium at concentrations of 40 ng ml in a solution prepared by dissolving a standard reference aluminium alloy was 213.9 +/- 1.3 ng. The relative standard deviation and the total error of the method (based on the SRM value) were 0.7 and 10.5% respectively.     

Substoichiometric determination of gold by neutron activation analysis

A rapid method has been developed for the determination of gold in catalyst samples by thermal neutron-activation analysis incorporating substoichiometric solvent extraction of Au/III/ with 1,2,3-benzotriazole /1,2,3-BT/ into n-butanol. The time required for radiochemical purification and counting of two samples and a standard was 1 h.     

Substoichiometric determination of Hg by radiochemical neutron activation analysis

A rapid method has been developed for the determination of mercury in environmental samples by thermal neutron activation analysis. Radiochemical separation involves the extraction of Hg/II/ with substoichiometric amounts of 2-mercaptobenzothiazole /2-HMBT/ into chloroform¹. The time required for radiochemical purification and counting of two samples and a standard is about 2 h. Water, sludge and IAEA standard samples were analyzed for Hg concentration by this method.     

The determination of gallium in rocks by neutron-activation analysis

Neutron-activation analysis has been applied to the determination of gallium in rocks. The Harwell Pile BEPO has been used as the source of neutrons, and a radiochemical procedure employing carrier chemistry has been utilised to separate the induced gallium activity.

Neutron-activation analyses of gallium in the standard rocks Gl and Wl are reported and compared with results obtained by other analytical methods.     

The determination of rhenium in rocks by neutron-activation analysis

Neutron-activation analysis has been applied to the determination of rhenium in rocks. Samples of the powdered rocks together with standards were irradiated in the Harwell Pile BEPO. Rhenium was separated from the irradiated rocks by a radiochemical procedure, using carriers, precipitations and solvent extractions. Radiochemically pure ¹⁸⁶Re was counted, and the chemical yield determined gravimetrically.Results for the rhenium contents of the standard rock samples G1 and W1 are reported. The ultimate sensitivity of the analytical method is ca. 5 × 10⁻⁵ ppm Re.     

Substoichiometric determination of traces of palladium by radioactive isotope-dilution analysis

A radioactive isotope-dilution method for the determination of traces of palladium has been developed. It is based on the solvent extraction of palladium dithizonate from acid solution by means of a substoichiometric amount of dithizone in carbon tetrachloride. The separation has been applied to the determination of traces of palladium in platinum, the rocks W-1 and PCC-1 and a biological material (kale). Amounts of palladium down to 3 ng have been determined.     

Substoichiometric determination of heavy rare earths by isotopic dilution analysis

A substoichiometric method for the determination of heavy rare earths (holmium, thulium) has been developed. After the addition of a substoichiometric amount of EDTA to the test sample of rare earth labelled with its radioactive isotopes, the negatively charged complex formed was separated by passage through a column of Dowex 50 x 8. Interfering metals can be removed by preliminary cupferron and diethylammonium diethyldithiocarbamate extraction. Concentrations of rare earth down to 4 x 10(-7)g 5 ml have been determined.     

Substoichiometric determination of traces of gold by radioactive isotope-dilution analysis

A radioactive isotope-dilution method for the determination of traces of gold has been developed. It is based on the solvent extraction of gold diethyldithiocarbamate from 0-5N sulphuric acid containing ascorbic acid, by means of a substoichiometric amount of zinc diethyldithiocarbamate in chloroform. The separation has been applied to the analysis of gold-doped semiconductor-grade silicon and of gold-bearing ores. Amounts of gold down to 5 x 10(-7)g 20 ml of test solution can be determined.