Determination of copper in zinc by proton activation analysis

A method for the determination of copper in zinc by proton activation analysis using the⁶³Cu(p, n)⁶³Zn reaction has been developed.⁶³Zn has to be separated chemically from gallium and copper activities formed out of the zinc matrix and from indium activity formed out of cadnium impurity. Gallium radionuclides are retained on a cation exchanger in chloride medium and the residual activity is extracted in di-isopropyl ether. Copper and indium are subsequently extracted with cupferron in chloroform. The method was applied to BCR reference materials with a copper concentration at the μg.g^?1 level. The detection limit amounts to 0.5 μg.g^?1.     

Determination of oxygen in fluoride glass by proton activation analysis

Oxygen was determined in three kinds of ZrF₄-based fluoride glass [ZrF₄–BaF₂–GdF₃–AlF₃ (ZBGA), ZrF₄–BaF₂–LaF₃–YF₃–AlF₃–LiF–NaF (ZBLYALN) and ZrF₄–BaF₂–LaF₃–YF₃–AlF₃–LiF (ZBLYAL)] used for fabricating optical fiberby¹⁸O(p, n)¹⁸F reaction without significant nuclear interference. The main long life⁹⁶Nb nuclide was produced by the⁹⁶Zr(p,n) reaction in a non-destructive analysis of ZBGA-fluoride glass and reduced by using a coincidence system with Ge(Li) and NaI(T1) detectors. Substoichiometric separation of¹⁸F was also used to determine oxygen in fluoride glass, especially in glass containing yttrium as a component element because the⁸⁹Zr produced by the⁸⁹Y(p,n) reaction is a positron emitter, the same as¹⁸F. It was confirmed that the oxygen concentration in fluoride glass was 13–2460 ppm related to the loss by scattering.     

Determination of metal traces in tantalum by proton activation analysis

Procedures for determining traces of calcium, titanium, vanadium, chromium, iron, copper, niobium, molybdenum and tungsten in tantalum are described utilizing 11 MeV proton activation. The instrumental method of analysis with the use of a Ge(Li) detector and the radiochemical separation of the corresponding fractions are described. The formula for the calculation of the concentration of traces with the use of thick target yields is given. Experimental data on the thick target yields of radioisotopes⁴⁴Sc,⁵²Mn,⁵⁶Co,⁶⁵Zn,^93mMo,⁹⁶Tc are presented. Based on the experimental data, the detection limits are estimated at 1–10 ppb for the above mentioned metal traces in tantalum. The successful solution of the task of the simultaneous determination of nine elements in tantalum confirms the wide applicability of proton activation analysis.     

Determination of arsenic in silicon matrices by proton activation analysis

Proton activation analysis is applied to the determination of As in high-purity silicon, ion implanted with nominal doses ranging from 10¹⁴ to 10¹⁶ atoms/cm². Both instrumental and radiochemical versions have been developed. The⁷⁵ As(p, n)⁷⁵Se,⁷⁵ As(p, 3n)⁷³Se and⁷⁵ As(p, pn)⁷⁴ As nuclear reactions have been considered in order to get the best activation conditions for delayed measurements by gamma spectrometry.     

Determination of thallium in environmental samples by activation analysis with fast reactors neutrons

A procedure is described for the determination of thallium in coal fly ash by fast neutron activation analysis using the reaction²⁰³Tl/n, 2n/²⁰²Tl. A 31 h reactor irradiatioon under cadmium cover at a fast neutron flux of 3.05×10¹² n.cm^–2.s^–1 is applied. The simple radiochemical separation involves a wet attack in acids followed by an extraction of Tl/III/into diisopropylether from 0.5M HBr. The radiochemical purity is sufficient for immediate -spectrometry. A value of 5.7±0.7 ppm is found in the NBS 1633a coal fly ash.     

Determination of sulphur in fly ash by instrumental proton activation analysis

A method for the determination of sulphur in fly ash by instrumental proton activation analysis using the³⁴S/p,n/^34mCl reaction was developed. The 2128.5 keV and 3305.0 keV -rays of^34mCl /t=32.0 min/ were measured on a Ge/Li/ -spectrometer, shielded with a lead absorber to attenuate low energy -rays. Irradiation and measuring conditions were optimized. The detection limit for instrumental analysis is 0.3 to 1 mg g^–1 and the standard deviation is cca. 4% for a typical sample.     

Determination of thallium in biological samples by thermal neutron activation analysis and low-level beta-counting

A procedure is described for the determination of thallium in complex biological matrices by thermal neutron activation analysis employing substoichiometric extraction of thallium(I) with 2-mercaptobenzothiazole (2-HMBT) at a pH of 7.5 into chloroform, and low-level beta-counting.     

Determination of lead,cadmium and thallium by neutron activation analysis in environmental samples

A radiochemical procedure for simultaneous determination of lead (²⁰³Pb), thallium (²⁰²TI) and cadmium (¹¹⁵Cd^115mIn) after fast neutron activation, based on ion-exchange separation from bromide medium and additional purification steps for Pb and Tl is described. Radioactive tracers²¹⁰Pb and¹⁰⁹Cd were used for determination of the chemical yields of Pb and Cd; for Tl it was determined gravimetrically. Two standard reference materials, BCR CRM No. 146 Sewage Sludge and NIST SRM 1633a Coal Fly Ash were analyzed and satisfactory agreement with certified values was obtained.     

Simultaneous determination of iron,cadmium and lead in zinc by proton activation analysis

Iron, cadmium and lead are determined in zinc by proton activation followed by chemical separation of the indicator radionuclides. The method provides detection limits of 0.03, 0.008 ad 0.1 μg g^?1 for iron, cadmium and lead, respectively. The BCR Unalloyed Zinc reference material 321 was analysed. Concentrations of 2.23, 0.215 and 4.641 μg g^? with 1–7% relative standard deviation were obtained for iron, cadmium and lead, respectively. These results contributed to the provisional certification of the reference material.     

Determination of zinc in clay and pottery materials by instrumental neutron activation analysis

The problems of determination of zinc in clay, ceramics and soils via ⁶⁵Zn using INAA are discussed. The applicability of different approaches for solving the influence of ⁴⁶Sc and ¹⁵²Eu by gamma-spectrometry on the line of ⁶⁵Zn at 1115.5 keV are experimentally evaluated. The application of the correction program ANGES for the calculation of the net peak area is demonstrated. All discussed approaches are checked by analyses of 10 SRM"s: Ohio Red Clay, Lefkandi brick, IAEA-SRM-Soil-1, IAEA-SRM-Soil-5, IAEA-SRM-Soil-7, IAEA-SRM-SL-3, GBW-08303, GBW-07406, NIST-SRM-2709 and BCR-SRM-520.     

Determination of chromium,iron and copper in niobium by radiochemical proton activation analysis

Chromium, iron and copper were determined in niobium by radiochemical proton activation analysis (PAA). The main steps of the technique involved the irradiation of the samples with 13 MeV protons, the post-irradiation decontamination of the sample surface, a two-step separation procedure based on anion exchange from HF and HCl medium, and counting the separated indicator radionuclides with a well-type NaI detector. For a 5-hr irradiation, limits of detection for chromium, iron, and copper were 0.2, 5.0, and 15 ppb respectively. The results obtained by this technique are compared with data obtained by radiochemical neutron activation analysis (NAA) and atomic absorption spectrometry (AAS).     

Determination of arsenic,cadmium and zinc in river water by neutron activation analysis

A concentration apparatus has been developed for the determination of As, Cd and Zn in water by neutron activation. The preconcentration technique used for this purpose is based on the retention of As, Cd and Zn on the Rexyn 201 resin at pH 10. The apparatus used minimizes the manipulations needed for preconcentration and contamination by trace elements present in reagents. Eleven samples of water from rivers in the Montreal region were analyzed and the following concentrations were found (in μg/1): As 0.86–1.95, Cd 0.61–0.98 and Zn 4.6–12.9.     

Determination of activable isotopic tracers of zinc by neutron activation analysis for study of bioavailability of zinc

A procedure of pre-irradiation concentration of zinc in fecal samples using anion exchanger was developed for the study of the bioavailability of zinc by neutron activation analysis. The mass ratios between⁷⁰Zn and⁶⁸Zn, or⁶⁴Zn and their contents between natural zinc and enriched zinc are used to calculate the bioavailability of zinc when the abundance of the isotope⁷⁰Zn is not high ehough.     

Determination of Ti,V, Zn and W traces by proton activation analysis

Procedures are described for determining traces of titanium in scandium, vanadium in titanium, zinc in copper and tungsten in tantalum, utilizing activation with 11 Me V protons. Experimental data on⁴⁸V,⁵¹Cr,⁶⁶Ga and¹⁸²Re yields and analytical sensitivities are reported.     

Determination of zinc in high purity bismuth by thermal neutron activation

A neutron activation analysis for the determination of zinc in bismuth was developed. After irradiating the samples for 44 days at 4·10¹¹n/cm²/sec, zinc was separated quantitatively by hexone extraction and precipitation as quinaldate. The sensitivity of the method was estimated as 0.05 p.p.m. No zinc could be detected in the high purity bismuth samples. An addition method of analysis showed that the precision was 1.2%.     

电感耦合等离子体原子发射光谱(ICP-AES)法测定再生锌中铊

铊是一种典型的危险废物,在选冶过程中,再生锌原料中的铊以氧化物或粉尘的形式排放到环境中,严重污染环境并危害人类健康。再生锌成分复杂,若样品消解不完全,直接影响测定结果的准确性。本文比较了微波消解和电热板常压消解对样品的处理效果。结果表明,微波消解法快速环保,但是对于难消解的再生锌样品,因无高氯酸的加入,其氧化性能降低,无法将样品消解完全,导致铊测定结果偏低。而采用高氯酸-硝酸-盐酸-氢氟酸构成的混合酸并于低温加盖聚四氟乙烯盖,进行电热板常压消解,能够有效地解决再生锌样品前处理难题。本实验采用四酸法消解样品,5%盐酸进行浸取,选择Tl 190.794nm为分析谱线,采用电感耦合等离子体原子发射光谱（ICP-AES）法测定再生锌中铊。在仪器设定的最佳测定条件下,当Tl质量浓度为0.10μg/mL~5.00μg/mL时,与发射强度线性关系良好,线性回归方程为y = 180.77x -0.46,相关系数为0.99998。干扰实验表明,在设定的共存离子干扰上限,Pb、Zn、Cu、Fe、Ca、Bi 、Sb、Sn、As、Al、Cd、Si、Ag等对再生锌中铊的测定基本无影响。按照实验方法,对5个不同铊含量水平的再生锌样品进行11次独立测定,其测定范围为ω(Tl):0.0041%~0.21%,方法检出限为0.004μg/mL,实验相对准偏差（RSD）为2.07%~3.11%,加标回收率为97.3%~107.5%。方法简单,操作性强,能够快速准确测定再生锌中铊。     

Determination of oxygen in alkali halide salts by proton activation and radiochemical separation

A lanthanum fluoride precipitation method for the separation of¹⁸F produced from the¹⁸O(p,n)¹⁸F reaction in alkali halide salts is described. This radiochemical separation method minimizes interferences from other positron emitters produced by proton bombardment and makes the accurate determination of ppm-level¹⁸O in complex alkali halide systems feasible. The interference from the¹⁹F(p,d)¹⁸F reaction is eliminated by keeping the proton energy less than 8.2 MeV. Applications of this technique to studies of dissolved oxide species in molten alkali halide salts are discussed.     

Determination of iodine concentration in aqueous solutions by proton activation analysis: preliminary results for digested human thyroids

The aim of our studies is to check the possibilities of using proton activation analysis as a competitive method over other analytical techniques applied for iodine determination. It is well known that long-term irradiation of biological samples leads to their decomposition and formation of gaseous radiolysis products, which increase the pressure inside the sample container. In case of using proton beam another problem with liquid samples appears. It is the production of ⁷Be via spallation reactions ¹⁶O(p, spall)⁷Be. The Compton effect from ⁷Be γ-line increases the detection limits for isotopes with low-energy γ-lines. AIC-144 cyclotron at The Niewodniczański Institute of Nuclear Physics Polish Academy of Science can accelerate protons up to energy of 60 MeV which is sufficient for (p,5n) reaction needed to obtain ¹²³I (T _1/2 = 13.27 h, Eγ = 159 keV, I = 83%) from stable ¹²⁷I, thus the Compton effect from ⁷Be was the main factor perturbing the analysis. Separation and removal of ⁷Be is required to improve the detection limit. The paper presents a method and an example of its application to the determination of iodine concentration in digested fragments of human thyroids obtained during surgical treatment of patients with different types of thyroid tumor.     

Determination of thallium by atomic absorption spectrophotometry

Summary The determination of thallium by atomic-absorption Spectrophotometry is described. Many substances interfere with the direct analysis of thallium under the conditions chosen. However, these interferences can be overcome by adding a lithium, potassium, or sodium buffer (5000 ppm). In this way the deviations caused by foreign substances can be reduced to less than ten per cent. Under the same conditions the effect of organic solvents has been studied.

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Zusammenfassung Die Bestimmung von Thallium mit Hilfe der atomaren Absorptionsspektrophotometrie wird beschrieben. Die direkte Bestimmung von Thallium wird im allgemeinen durch viele Fremdionen in höheren Konzentrationen gestört. Durch Verwendung eines Li-, K-, oder Na-Puffers (5000 ppm) können die Störungen auf weniger als 10% herabgesetzt werden. Unter den gleichen experimentellen Bedingungen wird die Wirkung von organischen Lösungsmitteln untersucht.