An internal standard method for the determination of tin and tungstein in cassiterite by photon activation analysis

A method is described for the simultaneous determination of tin and tungsten in cassiterite ores by photon activation analysis using both elements and zirconium and zinc as internal standards. By using a 15-MeV photon beam, some interfering reactions with higher threshold energies can be eliminated. Thus the data processing becomes simpler and more accurate. The proposed procedure can be used for the routine analysis of tin and tungsten in cassiterite samples.     

Determination of tin as stannite-kesterite and cassiterite in ores

Tin is stannite-kesterite and as cassiterite in a tin-bearing ore can be determined by the selective decomposition of the stannite-kesterite phase with a mixture of sodium nitrate and acetic acid.     

The determination of tin in tin ores and concentrates by atomic absorption spectrophotometry in the nitrous oxide-acetylene flame

Tin in tin ores and concentrates can be determined by atomic absorption measurement in the nitrous oxide-acetylene flame. Solutions are prepared by heating the samples with ammonium iodide and dissolving the resulting tin iodide in dilute hydrochloric acid. Calibrating solutions contain ammonium iodide and hydrochloric acid at approximately the concentrations present in the sample solutions. The method has a limit of detection of 0.02% tin in the sample and is suitable for application to geochemical prospecting samples. The results are similar to those obtained by standard chemical methods.     

Isotopic determination of48Ca by photon activation

An activation analysis method has been developed for the routine determination of⁴⁸Ca. The calcium is chemically separated, converted to the hydroxide, carbonate or chloride and activated for 30 min in the γ-ray flux generated by a primary electron beam between 40 and 57 MeV and a current of about 50 μA. A large number of samples can be activated simultaneously and the ratio of activities of⁴⁷Ca and⁴³K gives a measure of the isotopic concentration of⁴⁸Ca. Naturally-occurring⁴⁴Ca is used as an internal standard. The relative standard deviation is ±3.3%.     

The use of an activation detector in the determination of beryllium by photon activation

The determination of traces of beryllium in large samples by the (γ, n) reaction, using a¹²⁴Sb gamma-source, is in general hampered by the rather high handling costs when a BF₃ counter is used for the neutron detection. When manganese dioxide is used as an activation detector, the analysis is possible with a simple facility which can be stored in a water basin. The lower limit of the determination is ∼ 1 μg/g for a sample weight of 50 g.     

Multielement determination in tobacco leaves by photon activation analysis

A nondestructive photon activation procedure with 30 MeV bremsstrahlung followed by high-resolution gamma-spectrometry has been applied to the multielement determination in tobacco leaves and commercial cigarettes. The elements determined by this method included essential minor elements such as Ca, Cl, K and Mg, essential trace elements such as Fe, Mn and Zn, and possibly toxic elements such As and Sb. The NBS Orchard Leaves could successfully be used as a comparative standard. The method is quite simple and gives good reproducible results for at least 12 elements.     

The determination of tin in rocks by thermal neutron activation

A fast routine method for the determination of tin in rocks is discussed. The method is based on coprecipitation of tetravalent tin with ferric hydroxide, followed by a short irradiation in a high thermal neutron flux, extraction in toluene from 1∶1 sulphuric acid which is 5N in potassium iodide, and counting of^123mSn (T=40 m) or^125mSn (T=9.7 m) with a well-type NaI detector. In the present work^125mSn was used. The lower limit of determination is governed by the blank of the reagents. For a sample of at least one gram it is ≌ 0.2 μg Sn·g⁻¹.     

The determination of zirconium in biological materials by photon activation analysis

Non-destructive photon activation analysis with 30-MeV bremsstrahlung has been applied for the determination of zirconium in biological materials. The materials investigated were the NBS SRMs Orchard Leaves and Bovine Liver, and various tissues of rats. The detection limits of this method for a 2 h irradiation are 0.1 g for Orchard Leaves, 0.04 g for Bovine Liver and animal tissues. The zirconium contents of animal tissues obtained in this work appear to be significantly lower than the values reported earlier. New data on zirconium in the NBS SRMs are presented.     

Simultaneous determination of nitrogen and carbon in silicon by photon activation

The analytical procedure includes irradiation by 30 MeV photons followed by a chemical separation by evolution from molten KOH. Two radiochemical states of nitrogen are observed: NH₃ and N₂. Finally all nitrogen is converted to N₂, which is absorbed on titanium sponge. Carbon is converted to CO₂, which is absorbed in a KOH solution. This procedure was applied to silicon samples of various purity. Detection limits of 0.01 g carbon and 0.1 g nitrogen were achieved.     

The determination of some elements in rocks by instrumental photon activation analysis

This text describes the instrumental determination of some elements in silicate samples of ≃1 g by photon activation. The following elements can be determined: In acidic rocks: Mg, Ca, Ti, Mn, Sr, Zr and Nb, in ultramafic rocks: Mg, Cr, Ni, and Mn. The relative standard deviation is a few percent.     

The determination of tin in explosive materials by thermal neutron activation analysis

A method, based on the measurement of the -photopeak at 332 keV arising from a¹²⁴Sn(n, )^125mSn reaction, has been developed for the rapid measurement of Sn at concentrations of 20 g g^–1, present as the cross-linking agent, in explosive charges. The method is comparative, and has a limit of detection of 0.6 g g^–1 and a precision of 5% RSD. The method requires no sample preparation and is economical in effort.     

Neutron activation determination of impurities in high purity tin

A method of neutron activation determination of more than 20 impurities in high purity tin with an extraction separation of the matrix has been developed. The detection limits of impurities in the flux of 5·10¹² n·cm^?2s^?1 are on the level of 10^?5–10^?7%. Possibilities of instrumental determination of 11 elements are discussed.     

Multielement determination in floor sediments of the Japan Sea by nondestructive photon activation analysis

A nondestructive photon activation analysis with 30 MeV bremsstrahlung has been applied to the multielement determination in the floor sediments in a region of the Japan Sea. The abundances for 5 major and 11 trace elements were measured in several terrigeous and pelagic deposits, discussion being given on the results. Enrichments in certain trace elements, such as Mn, Ni and Co, were observed in the samples of pelagic areas, but to less extent relative to those of the mid-Pacific areas.     

Substoichiometric determination of rhenium in copper ores and molybdenum concentrates by neutron activation analysis

A simple and rapid substoichiometric method is described for the estimation of rhenium in copper ores and molybdenum concentrates by neutron activation analysis. 2 μg of Re can be determined with an accuracy of 4%. The variation of the mean at 95% confidence limit does not exceed 2%. The time required for processing three samples is less than 60 min.     

Highly accurate and precise multielement determination of environmental samples by means of photon activation using the internal standard method

In order to examine effective applications of the newly developed internal standard method, determinations of Cr, Co, Ni, Zn, As, Rb, Sr, Y, Zr, Nb, Cs, Ce and Pb in three environmental materials, such as pond, lake and estuarine sediments, have been tried by means of photon activation. In these examinations, some major constituent elements in the above sediments were properly used as excellent and effective internal standards. In consequence, it was confirmed that highly accurate and precise determinations of the above 13 elements were achieved easily and favourably.     

Determination of tin in ores and concentrates

A method is described for the determination of tin in cassiterite and stannite ores. The method is based on an ammonium iodide fusion of the ore under controlled heating conditions and the subsequent determination of tin by classical iodimetric technique.     

A specific method for the determination of uranium in ores by cathode ray polarography

A method is presented for the specific determination of uranium in ores by cathode my polarography. The uranium is separated by a simple and rapid mercury-cathode electrolysis, then determined polarographically in a base electrolyte in which vanadium, titanium and tungsten do not interfere. Application of the method to the analysis of ten standard uranium ores is shown.     

Titrimetric determination of uranium in low-grade ores by the ferrous ion-phosphoric acid reduction method

The modification and extension of the U.S.A.E.C. ferrous ion-phosphoric acid reduction method for the determination of uranium in high-grade or relatively pure material to a method for the determination of uranium with a high accuracy and precision, in ores containing 0.004-7% U is described. It is simple, rapid and requires no prior separations from elements that, in other methods, frequently interfere. For sample materials having very high concentrations of interfering elements, a prior concentration step using extraction with tri-n-octylphosphine oxide is described, but it is shown that, for most low-grade ores, this step is unnecessary.     

Fast determination of molybdenum and tellurium by neutron activation analysis

The utilization of 14.6-min ¹⁰¹Mo and 25-min ^101gTe for the determination of molybdenum and tellurium in biological materials by radiochemical neutron activation analysis is described for the first time. Radioisotopes were separated from the samples activated in a thermal neutron flux of about l0¹⁴n cm^-2 s^-1. The radiochemical procedure for molybdenum involves extraction of Mo⁺⁺ from 6 M HCl into diethylether, re-extraction into water, precipitation as oximate, and measurement of the gamma activity of ¹⁰¹Tc. The tellurium was separated by reduction to the element with SO₂ in 3 M HCl, dissolution in HNO₃, and reprecipitation as the element for the measurement of radioactivity. The sensitivity was estimated at ca. 10 ng at the level of confidence of 95%. The methods were tested by analyzing NBS- standard Bovine Liver and Orchard Leaves for molybdenum; the concentrations found were 3.2 ± 0.1 μg g^-1 and 300 ± 60 ng g^-1, respectively. The tellurium content of bovine liver was estimated at 90 ± 15 ng g^-1.     

The spectrochemical determination of indium in cassiterite

In order to determine the indium content of cassiterite specimens, a spectrochemical method, using tin as internal standard and the cathode-layer carbon arc, has been employed. The precision of the procedure is approximately 5 %.