Precise determination of aluminum by instrumental neutron activation

Because of the short half life of Al-28, the determination of aluminum by neutron activation is subject to many inaccuracies: variation of irradiation conditions between sample and standard, uncertainties in timing, and the effects of high and varying count rate, in addition to other sources of error that must be controlled even in work with long-lived nuclides. These errors can all be made smaller than the fundamental limit set by counting statistics, even when that limit is below 0.5 percent. The transfer function from the observed number of net counts to the counting rate at the end of irradiation is modeled as a product of three processes: radioactive decay and extending and nonextending dead time.The procedure has been applied to the analysis of NBS SRM 1633a Fly Ash. The mean concentration measured was 14.085% Al, with a standard deviation of the mean 0.023% Al for four determinations. The final results showed no significant imprecision beyond counting statistics. The accuracy of the method is shown by the analysis of high-purity single-crystal sapphire.     

Determination of aluminum levels in serum and red blood cells from long-term haemodialysis patients using instrumental neutron activation analysis

Aluminum levels of serum and red blood cell (RBC) were determined by instrumental neutron activation analysis (INAA) in 15 patients undergoing long-term haemodialysis. In the sample, aluminum was bombarded with thermal neutrons due to ²⁷Al(n,γ)²⁸Al and was determined by measuring 1779 keV gamma-ray of ²⁸Al (T _1/2 = 2.24 min) with a HPGe detector. Phosphorus, causing an important interference by the fast neutron reaction, ³¹P(n,α)²⁸Al, was determined by the photometric method to correct the net-area under the ²⁸Al gamma-peak. The one-sample Kolmogorov-Smirnov test was used to control the normality distribution of the aluminum levels in serum and RBC. The results obtained were found to be in agreement with the serum aluminum determination performed by electrothermal atomic absorption spectrophotometry. The statistical results show a correlation between the aluminum levels of serum and RBC. This revised version was published online in July 2006 with corrections to the Cover Date.     

Serum analysis of coronary heart disease patients by instrumental neutron activation analysis

Due to changes of the dietary pattern and life style, cardiovascular diseases like coronary heart disease (CHD) have been increasing in Korea. In this study, the levels of the serum minerals such as Na, Cl, K, Ca, Fe, Zn and Se for 75 patients with CHD and 25 normal persons, who were older than the age of 40, were investigated by instrumental neutron activation analysis. For analytical quality control, the reference materials. INSPQ and Seronorm, were analyzed simultaneously. The relative errors of the analytical values for the reference materials were within 10% of the certified values. The average concentrations of Na, Cl, K, Ca, Fe, Zn and Se in the serum of the male patients were 2,850±260 mg/1, 3,400±310 mg/l, 160±30 mg/l, 80.9±11.7 mg/l, 1.57±0.73 mg/l, 0.094±0.019 mg/l and 0.795±0.163 mg/l, respectively. The concentrations of Na, Cl, K, Ca, Fe, Zn and Se in the serum of the female patients were 2,890±240 mg/l, 3,430±350 mg/l, 169±27 mg/l, 81.8±13.0 mg/l, 1.26±0.44 mg/l, 0.099±0.015 mg/l and 0.769±0.105 mg/l, respectively. In a comparison between the patients and the normal group for both genders, while the levels of the elemental concentrations such as Na, Cl, K, Ca, Fe and Se were similar, the Zn concentration level of the CHD patients was significantly lower than that of the normal ones. The present study showed that the Zn concentration in the serum could be associated with CHD in Korean adults.     

Multielement determination in water by instrumental neutron activation analysis

Instrumental neutron activation analysis /INAA/ technique has been applied to a water sample to determine the elemental concentrations. The sample was irradiated with a neutron flux of 1.2×10¹² n cm^–2 s^–1 for two different periods followed by counting at three different decay times, using two coaxial type high-resolution Ge/Li/ detectors. The dominant elements determined in the water sample are Ca, Cl, Na, Mg, and K present in ppm-level while Co, I, Mn, Sm, and Sb are present in smaller amounts, approximately on the average 0.01 ppm. Only traces of other elements such as the rare-earth elements, Ag, As, Ba, Cu, Cd, Fe, Sr, W, Zn, seem to be present in the water sample.     

Aluminum determination by instrumental neutron activation analysis in tree barks

Journal of Radioanalytical and Nuclear Chemistry - Neutron activation analysis (NAA) for Al determination in tree bark samples containing phosphorus and silicon was studied. The contributions of...     

Multi-element determination in silicate rocks by instrumental neutron activation analysis

Instrumental neutron activation analysis technique was applied for the determination of 20 elements in 54 silicate rock samples which belong to three sedimentary geological formations located in the western desert of Iraq. The samples along with USGS standards were irradiated in an IRT-5000 reactor at a neutron flux of 3.7·10¹³ n·cm^–2·s^–1 The following minor and trace element constituents have been determined: Na, K, Ca, Fe, Sc, Cr, Co, Zr, Ce, La, Nd, Sm, Eu, Tb, Yb, Lu, Hf, Ta, Th and U.     

Multi-element determination in sandstone rock by instrumental neutron activation analysis

Summary Instrumental neutron activation analysis (INAA) was used for the qualitative and quantitative analysis of sandstone samples of Aswan area, in South Egypt. The samples were properly prepared together with standards and simultaneously irradiated by a neutron flux of 7 ^. 10¹¹ n ^. cm^-2.s^-1. in the TRIGA research reactor facilities in Mainz. The gamma-spectra from a hyperpure germanium HPGe detector were analyzed. The present study provides the basic data of elemental concentrations of a sandstone rock. The following elements have been determined: Na, K, Fe, Sc, Cr, Co, Zr, Ce, La, Nd, Sm, Eu, Yb, Lu, Hf, Ta, Th and U. Energy dispersive X-ray fluorescence (EDXRF) was used for comparison and to detect elements which can be detected only by this method.     

Multielement determination in soil extracts by instrumental neutron activation analysis

Forest Swiss soils from 39 locations sampled ad three depths each were extracted with a buffered solution of pH 4.65 containing EDTA. Nearly 30 elements were determined by instrumental neutron activation analysis in these extracts. The results obtained are discussed in terms of efficiency of the extractant, precision and accuracy. Summariszed results are presented for the quantities fractions of the elements extracted.     

Rapid determination of halogens in milk by instrumental neutron activation analysis

The absolute concentrations of iodine, bromine and chlorine in milk, have been determined by epithermal neutron activation followed by high resolution gamma-ray spectrometry. Two kinds of milk commonly consumed in Israel have been investigated. The concentration of iodine, bromine and chlorine were found to be 0.18–0.30 g/ml, 2.02–2.85 g/ml and 0.65 mg/ml, respectively. The method is fast, selective, accurate and highly sensitive.     

Silicon determination in plant materials by instrumental epithermal neutron activation analysis

The Si determination with epithermal neutrons using the reaction²⁸Si (n,p)²⁸Al is described. Thermal neutrons are eliminated from the irradiation position with a BN-shield. Two first order interfering reactions with P and with Al necessitate appropriate corrections. The interfering reaction on Al is shown to depend heavily on the hydrogen (H) content of the sample, which therefore must be taken into account. The lower application range in plant samles is estimated to be 500 g g^–1. Reproducibility is <5% in suitable cases, but not as good if the necessary corrections are large. The capacity is 25 samples per 8 h. The method is applied to 3 plant standards (rice, hay and pine needles) and to 47 samples of spruce needles. The applicability to different plant materials is mainly limited by their relative Al, P and Si concentrations. Literature values are use to find plant categories in which Si can be reasonably determined by instrumental epithermal neutron activation analysis (IENA).     

Trace element determination in high-purity aluminum clad samples by k 0-based internal monostandard instrumental neutron activation analysis

The k₀-based internal monostandard instrumental neutron activation analysis (IM-INAA) method was applied for quantification of trace impurities in seven high purity aluminum samples used as fuel cladding in a research reactor. Samples along with BCS CRM 182 (Si–Al alloy) were irradiated in high flux reactor neutrons for 10–15 h. In situ detection efficiency, needed in concentration calculation ratio by IM-INAA, was obtained using gamma rays of activation products produced in the samples. Elemental concentration ratios obtained with respect to Fe (used as internal monostandard) were converted to absolute concentrations by determining concentration of Fe by relative method of NAA. Concentrations of ten trace elements (Sc, Cr, Co, Zn, Ga, La, Ce, Sm, W and Hf) including major element Fe were determined in this work. The method used is non-destructive in nature and does not need multielement standards. Results of IM-INAA were compared with those obtained by relative method of INAA and inductively coupled plasma atomic emission spectrometry (ICP-AES). Details of methodologies and results obtained by all methods are discussed and compared in the paper.     

Intercomparison and determination of environmental standard samples by instrumental neutron activation analysis

To identify and improve the analytical technique for air pollution research, four kinds of environmental standard samples, i.e., airbome particulate matter, coal flyash, soil and pine needle supplied from the NIST and the IAEA were analyzed using thermal and epithermal neutron activation techniques. Sample irradiation was done at the irradiation facilities (neutron flux, 1 · 10¹³ n·cm^–2·s^–1) of the TRIGA MARK-III Research Reactor in the Korea Atomic Energy Research Institute. The accuracy and precision for the analysis of 40 trace and toxic elements in the samples were compared with the certified and reported values, respectively. In the analytical results of all standard reference materials, the relative standard deviation were within the 15% except for 11 elements and the relative error were agreed within the 10–20% except for 13 elements. The benefit of epithermal activation was investigated and the optimum analytical condition is reported.     

Multielement determination in cattle hair infested withBoophilus microplus by instrumental neutron activation analysis

Instrumental neutron activation analysis (INAA) was applied to estimate the concentrations of Ca, Co, Cr, Cu, Fe, K, Mg, Mo, Mn, Na, Se and Zn in hair samples from Holstein-Friesan male calves, which were infested withBoophilus microplus larvae and, also from healthy animals. These results were obtained in order to evaluate if is there a significant difference between the trace element concentrations in hair samples from infested and healthy animals.     

The determination of bromine in dry biological material by instrumental neutron activation analysis

Procedures for the determination of bromine by the reactions⁸¹Br(n, γ)⁸²Br (T=35.4 h) and⁷⁹Br(n, γ)^80mBr (T=4.4 h). In the case of⁸²Br a flat coaxial Ge(Li) crystal is used to measure the 619 keV photopeak. For^80mBr a planar Ge(Li) detector is applied to measure the 39 keV γ-ray. The agreement between the data obtained with both techniques for some Standard Reference Materials is satisfactory.     

Rapid determination of selenium in various marine species by instrumental neutron activation analysis

Instrumental neutron activation analysis was used to determine selenium concentrations in several marine organisms including two certified reference materials /NRCC lobster hepatopancreas, NBS oyster tissue/ and one uncertified material /IAEA fish homogenate/. The⁷⁶Se/n, /^77mSe/T=17.4 s/ reaction was successfully employed to achieve an overall precision between 3–10% and detection limits between 0.3–0.6 g/g. The accuracy of the results, as compared to the certified values, was in excellent agreement with the NBS material and only slightly lower /9%/ for the NRCC material.     

The determination of trace-element impurities in natural diamonds by instrumental neutron activation analysis

On applique la technique d'analyse par activation neutronique non destructive, utilisant un détecteur Ge(Li) à haute résolution pour déterminer des traces d'impuretés dans des diamants. La présence de 40 éléments est mise en évidence dans les diamants naturels. On donne des résultats quantitatifs portant sur 13 éléments dans 25 échantillons de diamant représentatifs d'une même origine. Un rapport a été établi entre la chimie des inclusions et la couleur des diamants d'une part, et les traces des éléments trouvés d'autre part.      

Quantitative determination of In and Sn in cassiterites by instrumental neutron activation analysis

Indium (10–15,000 ppm) and tin (20–90%) are quantitatively determined in cassiterite samples by instrumental (thermal) neutron activation analysis, using semiconductor detectors and gamma spectroscopy. Precision is 7% or better for In and 5% or better for Sn. The detection limit is 2 ppm for In and 0.4% for Sn in Mexican cassiterites.     

The determination of zonally distributed impurities in diamond by instrumental neutron activation analysis

A technique is described for the determination by instrumental neutron activation analysis of the zonal distribution of trace elements in diamond. Individual diamonds were irradiated and then dissolved in stages into 10 to 20 fractions in molten sodium nitrate. The activity of the material dissolved in each fraction was measured using a well-shielded Ge(Li) detector. Because of the small sample sizes involved, many elements typically found in diamond were below the limits of detection even though the experimental conditions were optimised for high sensitivity. The data obtained for a clear, a green and a coated diamond are given here to show the scope of the method. High levels of some elements in the outermost layers of all the diamonds are thought to have been due the implantation of surface contaminants during neutron irradiation. Removal of the outer few microns of irradiated diamonds before counting will avoid this source of error.     

Erros in instrumental neutron activation analysis

Equations are derived for the statistical and systematic error in INAA. It is possible to use them for the definition of limits of decision, detection and determination.     

Errors in instrumental neutron activation analysis

Equations are derived for the statistical and systematic error in INAA based on single photopeaks. They may serve to predict the applicability of the method or to judge data obtained under well-known conditions.