Elemental composition of vegetables cultivated in illegal mining towns in Ghana using neutron activation analysis

The elemental concentrations of 12 elements from five species of the most consumed vegetables in Ghana cultivated in five mining and three non-mining towns have been analyzed using neutron activation analysis. About 50% of the total concentrations recorded for cadmium and arsenic for the various towns and vegetables were found to be above the World Health Organization (WHO) permissible levels. The statistical methods employed in this work also provided more understanding on the geographical distribution of the elements, vegetables and sampling towns. The principal component analysis of our data showed two major clusters consisting of gold mining towns and non-gold mining towns in relation to the elemental concentrations of vegetables cultivated in these towns.     

Determination of gold in platinum by neutron activation analysis

The determination of gold in platinum by neutron activation analysis is described. The possibility of screening out the influence of the nuclear reactions on the final result of the determination was studied. In the case of microamounts of gold in platinum, gold was separated previously by extraction chromatography with dithizone as organic stationary phase. Gold fixed on the column was irradiated and determined gamma-spectrometrically.     

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.     

14 MeV neutron activation analysis of gold jewellery

Samples of nominal 18 carat and 21 carat gold jewelleries from the local market were non-destructively bulk analyzed using neutron activation analysis. Neutrons of 14 MeV energy were used with a fast pneumatic sample transfer system. The actual gold contents, as well as the composition of the base metals in these samples were determined. The fast neutron activation was found to be an efficient, quick and accurate method of characterizing the precious metal objects routinely in bulk, with a large sample throughput. The results demonstrate the commercial availability of the technique for non-destructive bulk analysis of precious metal objects.     

The use of neutron activation in dietary reference material analysis

Summary Results for a number of trace elements in a total human diet material (USDIET-1), obtained by the application of both INAA and RNAA are presented. Several dietary reference materials such as NBS SRM 1577A, and BCR CRM Single Cell Protein were also analyzed, and these results are also given. Combining measurements on short and long lived radionuclides, the INAA approach is useful for the determination of about 20 elements. In order to expand the elemental coverage or improve detection limits, RNAA was also explored in two modes: separation of radionuclides using organic ion exchange resins and the use of hydrated manganese dioxide. This combination is applicable to 15 trace elements. For example, using RNAA, the following results were obtained for USDIET-1: Cd=31.8, Mo=280, Cr=71, Ag=4, As=117 and Sb=9.4 g/kg. In the INAA mode, special attention was given to Al, F and Se. The F content of USDIET-1 was found to be 840 mg/kg, a rather high value, resulting from handling USDIET-1 by Teflon tools. By applying INAA and RNAA under two different laboratory conditions, it has been demonstrated that, even for the so-called difficult to determine elements like Cr, As or Mo, consistent results can be obtained. Thus, NAA promises to be a strong tool for human nutritional studies.

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Einsatz der Neutronenaktivierung für Nahrungsmittel-Referenzmaterialien

     

Trace analysis of ancient gold objects using radiochemical neutron activation analysis

Radiochemical neutron activation analysis has been applied to investigate the microelements in gold samples with archaeological importance. Chemical separation has allowed the determination of traces of Ir, Os, Sb, Zn, Co, Fe, Ni. Instrumental neutron activation analysis has been used for the determination of Cu.     

Determination of gold in biological materials by radiochemical neutron activation analysis

A radiochemical neutron activation analysis procedure was developed for the determination of trace amounts of gold in biological materials. The procedure was realized with irradiation of reference and test samples in a nuclear reactor, selective and quantitative separation of gold using inorganic MnO₂ Resin and gamma-ray spectrometric measurement of ¹⁹⁸Au. The method is characterized by a low limit of detection of gold at ng g^?1 level. Results shows that the method can be applied to the determination of trace amounts of gold in tissues for medical research.     

Substoichiometric neutron activation determination of gold

A highly precise and selective method is described for the determination of traces of gold by substoichiometric extraction from hydrochloric acid with tri-n-octylphosphine sulfide in cyclohexane following thermal neutron activation. Fundamental aspects of the extraction system are discussed and results are reported for the determination of gold in an effluent from a recovery process.     

Application of instrumental neutron activation analysis to plant medicines in Ghana: A review

Some essential elements in eleven plant medicines used at the Center for Scientific Research into Plant Medicine (CSRPM), Mampong-Akwapim, Ghana, for the management and cure of various diseases were determined by instrumental neutron activation analysis (INAA), using thermal neutrons at a flux of 5^.10¹¹ n^.s^-1.cm^-2. The plant medicines were: Sirappac powder-E, Tina-A powder, Blighia powder, Aphrodisiac powder, Ninga powder and Lippia tea. The others are Olax powder, Ritchiea powder, Momordica powder, Kenken and Fefe powder. Concentrations of seventeen elements namely Al, Br, Ca, Cl, Co, Cu, Cr, K, Mn, Mg, Na, Rb, Sb, Sc, Ta, V, and Zn have been determined by short, medium and long irradiation times. Of these elements Co, Sb, and Sc are found to be present at the trace level, Br, Cu, Cr, Mn, Rb, Ta, V and Zn at the minor level, while Al, Ca, Cl, K, Mg and Na were generally at major level. The differences in the concentration of the elements are attributed mainly to soil composition and climate in which the plants grow. Standard reference material NIST SRM-1571 (Orchard Leaf) was analyzed simultaneously with the samples. The precision and accuracy of the method were evaluated using real samples and the standard reference material. It was found that the elemental concentrations measured in the NIST SRM-1571 were within ±10% of the reported values. The importance of these elements as related to human health and nutrition has been discussed.     

Simultaneous determination of mercury and gold in bismuth by neutron activation analysis

After adding mercury as carrier, trace amounts of mercury and gold were simultaneously separated from bismuth by coprecipitating with sulfur produced by the decomposition of bismuth sulfide. The sulfur was filtered on a membrane filter, and the γ-activities were measured with a Ge(Li) detector. The recoveries were quantitative and the measurement of chemical yield was unnecessary. 123 ppm of mercury and 8 ppb of gold in a bismuth sample were determined simultaneously.     

Assay of platinum and gold in biological material by neutron activation analysis

Compounds of both gold and platinum are used in medicine, the former as salts to treat arthritides and the latter as the metal complex cisplatin to treat cancer. We have investigated neutron activation analysis with the Slowpoke II reactor as an assay method for both elements using human blood plasma as a matrix. Neutron activation of platinum gives rise to 3.15 day¹⁹⁹Au while that of gold produces 2.7 day¹⁹⁸Au. Activated samples are dissolved during heating in test tubes and the gold extracted by adding dibutyl sulphide to the same tube. The latter is formed to able to quantitate Pt down to 60 ng and Au down to 60 pg. The dissolution technique and possible interferences in the assay are discussed.     

Determination of platinum and gold in biological materials by neutron activation analysis

A procedure for platinum and gold determination utilizing, neutron activation combined with radiochemical separation, has been developed. The reaction¹⁹⁸Pt (n, )¹⁹⁹ is used for Pt determination. Four procedures for gold separation are examined: (1) adsorption on untreated polyurethane foam (UPF). (2) extraction with dibutyl sulphide. (3) reduction of gold to elementary state in conc. H₂SO₄, and extraction of gold as diethyldithiocarbamate complex. The extraction with Cu(DDC)₂ is chosen as the most suitable process and applied to platinum and gold determinations in Bowen's Kale and mice organs, previously treated with Biocisplatinum^® specimens.     

Determination of gold in some myanmar indigenous medicines by neutron activation analysis

Gold has been determined in two Myanmar indigenous medicines TMF 14 (Devaauthada), TMF 15 (Shwe Thwe Say) by neutron activation analysis using an Am(Be) radionuclide neutron source. The activity of 411 keV of the¹⁹⁸Au has bene measured.     

Large sample neutron activation analysis of dross for gold and silver

Large sample neutron activation analysis of dross from India Government Mint, Mumbai was carried out for quantification of gold (Au) and silver (Ag) using graphite reflector position of Advanced Heavy Water Reactor critical facility at Bhabha Atomic Research Centre, Mumbai. The k ₀-based internal monostandard NAA was used to calculate concentration ratios of Au and Ag with respect to sodium (Na), which was used as an internal monostandard. The concentration ratio values of Au to Na of varying mass of dross showed that mass ≥2 g was the representative sample size for analysis. Concentrations of gold and silver were found to be in the range of 200–400 and 1200–1700 mg kg^?1, respectively in three different samples.     

Assessment of gold exposure and contamination in galvanizing workplace by neutron activation analysis

Gold is not included in the current list of elements considered essential to humans and there are many controversies related to its toxicity. According to the chemical characteristics of the element, Au¹⁺ is favored for binding at sites with S donor, such as sulfhydryl group (-SH) in proteins in biological systems. This tendency raises the possibility of health-related risk, mainly linked to a long-term exposure to high and low levels of gold. This paper highlights the determination of gold by instrumental neutron activation analysis (INAA) during the assessment of exposure levels to metals and possible workers’ contamination in three galvanizing factories applying the same processes. This assessment is aimed at giving support to Worker’s Health Awareness Program of the Municipal Department of Health of Belo Horizonte, Minas Gerais, Brazil. INAA, mix of k ₀ and monostandard methods was applied to air filter, hair and toenail samples, and to urine samples. Solvent extraction of gold was carried out followed by comparative INAA. The results revealed that gold was present in all matrixes, indicating the exposure in the workplace and suggesting endogenous contamination. Is gold playing a role as a toxic element?     

The simultaneous determination of silver,gold and mercury in high-purity lead by neutron activation analysis

A radiochemical method was developed to separate the group of the noble metals simultaneously from a lead matrix after irradiation with thermal neutrons. The resulting complex γ-spectrum was resolved by matrix calculus. Smoothing of the obtained data to determine the presence of small photopeaks among the background fluctuations, was done by convolution, based on a least squares approximation. The interference of antimony and bromine was studied. Amounts as low as 20–30 p.p.b. of Hg and less than 1 p.p.b. of Au were determined in the presence of up to 9 p.p.m. of Ag.     

The use of neutron activation for routine analysis of pure iron and chromium

A method is presented for the routine analysis of high-purity iron and chromium by neutron activation analysis. The impurities determined are those which are significant in the control of the purification processes. Nine elements are determined in iron without separation; Co, Cr and Mo can also be determined after an anion-exchange separation. In chromium, a single elution on an anion exchanger allows the detection of nine significant impurities. For the determination of nickel a special method is used. All these methods were chosen to obtain the most comprehensive analytical procedure at the lowest cost.     

Determination of gold by non-destructive activation analysis for purposes of geochemical and geobotanical prospecting

Summary The correlation between gold content of rocks, ores and natural waters and plants from gold bearing areas for purposes of geochemical and geobotanical prospecting is being investigated. Non-destructive activation analysis was found to be advantageous for these purposes. The preliminary field study of samples obtained from an abandoned gold mine in the Bockhart area near Bad Gastein in Austria and from its environment is also described.

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Zusammenfassung Die Korrelation zwischen dem Goldgehalt von Gesteinen, Erzen sowie natürlichen Wässern und Pflanzen aus goldhaltigen Gebieten zwecks geochemischer und geobotanischer Prospektierung wird untersucht. Für diese Aufgaben erwies sich die zerstörungsfreie Aktivierungsanalyse als vorteilhaft. Das mit Hilfe von Feldmethoden ausgeführte, vorläufige Studium von Proben, die aus einer verlassenen Goldmine im Bockhart-Gebiet in der Nähe von Bad Gastein (Österreich) und ihrer Umgebung erhalten wurden, wird gleichfalls beschrieben.

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Dedicated to ProfessorE. Broda for his 60th Anniversary.     

Determination of nanogram quantities of gold in biological tissues by nondestructive neutron activation analysis

We describe a method for gold analysis in kidney and liver. The technique is simpler than other methods in that it does not require ashing or acid digestion of the sample. The tissue is dried, placed into a polyethylene vial and diluted with a 2 ml sodium chloride solution. Gold concentration is determined by neutron activation analysis. Samples are irradiated for two hours at a thermal neutron flux of 10¹²n·cm⁻²·s⁻¹ and are then allowed to decay for 3–4 days before counting. The detection limit (20 ng Au/ml) and precision (±6.1%) permits the accurate analysis of gold in these tissues. This technique could aid in a re-examination of gold metabolism.