Determination of molybdenum in biological materials by neutron activation

A method of the determination of molybdenum in biological materials by neutron activation is described. The method is based on the γ-spectrometric measurement of^99mTc after radiochemical separation of the latter by substoichiometric extraction with tetraphenylarsonium chloride using rhenium as inactive carrier. The method has been tested with reference materials.     

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.     

Simultaneous determination of iodine and selenium in biological samples by radiochemical neutron activation analysis

Summary Regarding the favourably sensitive nuclear characteristics of iodine and of selenium but the very different half lives of their induced nuclides ¹²⁸I and ⁷⁵Se, a radiochemical neutron activation analysis method for simultaneous determination of these elements in a single sample was developed. It is based on the double irradiation LICSIR technique — Long Irradiation for Se (40h), Cooling (a week or more), Short Irradiation for iodine (1–15 min) with following Radiochemistry. After the second short irradiation, the sample is ignited in an oxygen flask and iodine and selenium are sequentially and selectively extracted as elemental iodine and 5-nitro-2,1,3 benzoselena diazole chelate. With the described method biological samples were analysed and the reliability of the results was checked by the analyses of different standard reference materials. Good agreement with certified values and high radiochemical purity of the spectra show the applicability of the radiochemical separation developed.     

Separation of131I by isotopic and non-isotopic liquid ion exchange

A study is presented on the use of isotopic and non-isotopic ion exchange in a heterogeneous liquid-liquid system for the separation of¹³¹I from water. The method is based on the reaction between radioiodide in the aqueous phase and trioctylmethylammonium iodide or chloride in the organic phase. The effect of some important experimental parameters on the separation efficiency is discussed. It has been found that under optimum conditions the method of isotopic ion exchange can be used for the radiochemical determination of iodine in water.     

Determination of cobalt by substoichiometric thermal neutron activation analysis

A selective method has been developed for the determination of traces of cobalt in different matrices by the sensitive technique of thermal neutron activation analysis employing radiochemical separation and substoichiometric extraction of Co/II/ with iso-nitrosobenzoylacetone into chloroform.     

Determination of cesium in seawater by radiochemical methods

Radiochemical methods for the determination of cesium in seawater are described. Preliminary substoichiometric concentration with nickel hexacyanoferrate(II) and tetraphenylborate and application of selective radiochemical techniques are used. The cesium content in Atlantic Ocean samples is 0.74 ± 0.03 μg l^-1. The method is applicable on board ship. The approach should be generally useful.     

Rapid radiochemical neutron activation analysis for iodine in urine by different separation techniques.

In the present work on radiochemical neutron activation analysis for the determination of iodine in urine samples, the performance of three different radiochemical separation techniques, namely, direct extraction, use of an iodinated ion-exchange resin column and Sch?niger combustion, were intercompared and validated. The practical advantages of the iodinated-resin technique make it most suitable for the rapid routine determination of iodine in urine. It was further verified by participation in an international intercomparison run of urine analysis, and used in a pilot study on iodine determination in the urine of 171 Slovenian schoolchildren, where it gave results in good agreement with the catalytic method.     

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 μg 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.     

Radiochemical separation and determination of platinum,gold and palladium in complex matrices employing substoichiometric thermal neutron activation analysis

A radiochemical separation method has been developed for the separation of platinum, gold and palladium from various matrices by thermal neutron activation analysis and employing substoichiometric extractions of Pt and Au with 2-mercaptobenzothiazole and Pd with isonitrosobenzoylacetone. Decontamination factors for the individual elements after separation was also studied and was found to be greater than 10⁵ for most of the elements.     

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.     

Determination of caesium microamounts by isotope dilution with substoichiometric separation

Selectivity of isotope dilution analysis with substoichiometric separation for caesium determination has been investigated. Caesium can be extracted with a substoichiometric amounts of bis 1,2-dicarbollylcobaltate in nitrobenzene in the presence of dibenzo-18-crown-6. The method is selective. Other metal ions (K⁺, Na⁺, Mg²⁺, Ca²⁺, Fe³⁺, Al³⁺) do not interfere.     

Determination of copper in biological samples by substoichiometric neutron activation analysis

A method has been described for the determination of trace amounts of copper in biological samples by thermal neutron activation analysis, involving radiochemical separation of copper from irradiated matrix employing substoichiometric extraction of Cu/II/ with 2-mercaptobenzothiazole /2-HMBT/ into chloroform. 4.01 g of Cu/II/ can be determined with an accuracy of 3.13% and precision of 1.08%.     

Substoichiometric extraction of metals and its application to the determination of heavy metals in environmental samples by neutron activation analysis

Solvent extraction as a technique for the separation of ionic solutes and the advantages and application of substoichiometric extraction in neutron activation analysis have been discussed. The application of this technique has been elucidated with reference to the determination of Zn, Cd and Hg in environmental samples. The decontamination factor, accuracy, precision, sensitivity and radiochemical purity of the separated fraction have been discussed.     

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.     

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.     

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.     

Determination of microamounts strontium by substoichiometric isotope dilution analysis

The isotope dilution with substoichiometric separation for the determination of strontium has been investigated. Strontium can be extracted with a substoichiometric amount of bis-1,2-dicarbollylcobaltate in nitrobenzene in the presence of 15-crown-5. It has been found, that Li⁺, Mg²⁺, Ca²⁺ and Fe³⁺ do not interfere in the strontium determination but the high extraction of K⁺, Na⁺ and NH₄ ⁺ ions results in marked influence.     

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%     

Indirekte photometrische Bestimmung kleiner Jodmengen in Selen

After separation of selenium by precipitation with ferrous iron, the iodine is employed for catalyzing the Ce⁴⁺/As³⁺-redox reaction. This is stopped by ferrous iron and the ferric iron formed is determined by photometry as thiocyanate. This method enables the determination of about 100 ± 6 ng of iodine in 5–10 mg of selenium. The method was applied for determination of the distribution of iodine in Se-rectifier layers. The layers were dissolved by etching with a solution of alkali cyanide. The usual doping elements showed no disturbance.