Determination of metal concentrations in lichen samples by inductively coupled plasma atomic emission spectroscopy technique after applying different digestion procedures

Three digestion procedures have been tested on lichen samples for application in the determination of major, minor and trace elements (Al, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, V and Zn) in lichen samples collected in Aegean Region of Turkey by inductively coupled plasma atomic emission spectrometer (ICP-AES). The acid mixture of concentrated HNO₃, H₂O₂ and HF were used. The instrument was optimized using lichen matrix considering RF power, nebulizer pressure, auxiliary flow rate and pump rate. The accuracy of the overall analyses was first estimated by analysis of two certified reference materials. Good agreement between measured and reference values were found for almost all elements. As the second way of determining the accuracy, results obtained from independent analytical techniques (ICP-AES and instrumental neutron activation analysis (INAA)) were compared for all elements by analyzing real samples. Correlation coefficients of two techniques for the elements ranged between 0.70 (Mg) and 0.96 (Fe). Among the three digestion systems, namely microwave, open vessel and acid bomb, microwave digestion system gave the best recovery results. The method detection limit (MDL) was computed using reagent blanks of microwave digestion system since it provides cleaner sample preparation. Detection limit is adequate for all elements to determine the elements in lichen samples. The precision was assessed from the replicate analyses of reagent blanks of microwave digestion system and was found to be less than 1.5% relative standard deviation (R.S.D.).     

The k 0 and relative INAA methods to determine elements in entire archaeological pottery objects

The advantages of instrumental neutron activation analysis applied to archaeological ceramics have been enhanced through the analysis of entire objects, using both the k ₀ method and the relative method, respectively, to determine the concentrations of chemical elements in aliquots of replicate objects used as comparators and in the sample object. Twenty-two chemical elements of archaeological importance were measured in mud figurines from Caral civilization (5000 year BC), irradiated inside a well-characterized radial channel facility of the nuclear research reactor at IPEN, Peru. The results showed less than 10 % of bias for most of the elements.     

The role of different soil sample digestion methods on trace elements analysis: a comparison of ICP-MS and INAA measurement results

The measurement of trace-element concentration in soil, sediment and waste, is generally a combination of a digestion procedure for dissolution of elements and a subsequent measurement of the dissolved elements. “Partial” and “total” digestion methods can be used in environmental monitoring activities. To compare measurement results obtained by different methods, it is crucial to determine and to maintain control of the bias of the results obtained by these methods. In this paper, ICP-MS results obtained after matrix digestion with modified aqua regia (HCl+HNO₃+H₂O₂) method and two “total” digestion methods (microwave aqua regia+HF and HNO₃+HF) are compared with those obtained by instrumental neutron activation analysis, a non-destructive analytical method for the determination of the total mass concentrations of inorganic components in environmental matrices. The comparison was carried out on eight agricultural soil samples collected in one test area and measured by k₀-INAA and ICP-MS to determine As, Co, Cr, Sb and Zn mass concentration. The bias of results for As, Cd, Co, Cr, Cu, Ni, Pb, Sb and Zn of the three digestion methods were assessed using selected measurement standards. This paper highlights that the digestion procedure is an integral part of the measurement and can affect the measurement result in environmental analysis.     

Comparative study of different digestion procedures using supplementary analytical methods for multielement-screening of more than 50 elements in sediments of the river Elbe

The suitability of four different digestion procedures, i.e. i.) an aqua regia digestion according to DIN 38 414-S7, ii.) a pressure digestion using HNO₃/HF in PTFE-vessels, iii.) a HNO₃/HF + HCl-pressure digestion in PTFE-vessels and iv.) a HNO₃/HF + HCl-pressure digestion using microwave induction, has been evaluated with regard to the quantitative determination of about 50 elements in environmental samples. Three sediments of the river Elbe and two standard reference materials (MESS-1 and NIST 1645) have been employed. The analytical results from the dissolved samples, obtained using inductively coupled plasma mass- and optical emission spectrometry as well as total reflection X-ray fluorescence spectrometry, have been compared with those obtained by instrumental neutron activation analysis. Only digestion procedures using HNO₃/HF with a subsequent evaporation to dryness and dissolution in HCl have led to appropriate results for a wide range of elements (more than 50 elements in total). Because of its low contamination risk and its time saving, the microwave digestion is preferred. For this digestion procedure the accordance among the different instrumental methods used is high (better than 15% deviation) in general. A few elements (16) could be determined quantitatively only by a single method.     

Application of prompt gamma-ray analysis and instrumental neutron activation analysis to identify the beef production distinct

We present chemometric study to identify the provenance of agricultural product, beef. Combination of instrumental neutron activation analysis (INAA) and prompt gamma-ray analysis (k ₀-PGA) were performed to determine 10 elements, C, H, N, S, Sm, Br, Mg, Na, K, Cl, nondestructively. We measured elemental profiles in beef samples produced from different districts in Japan, Australia and USA. In the case of PGA, k ₀-method was employed to determine the elemental concentrations. There was a difference in elemental profiles between Japanese black cattle beef and that produced in USA through principal component analysis (PCA). However, Holstein beef of Japan and that of Australia was not sufficiently grouped by the PCA modeling with the elemental data set. This is the first study to identify the provenance of beef through elemental analysis.     

Characterization of Geological Certified Reference Materials by Inductively Coupled Plasma-Mass Spectrometry

A rapid, safe, and efficient microwave-assisted acid digestion method is reported to determine thirty-six elements in three international geological reference materials and two in-house reference materials using high resolution inductively coupled plasma mass spectrometry. This method was also employed to determine the radiogenic isotopic composition of Sr and Nd in two geological reference materials by multicollector inductively coupled plasma mass spectrometry. In order to ascertain the most suitable preparation method, four microwave-assisted digestion procedures were compared. The presence of insoluble fluorides on the recoveries of Ba, Rb, Sr and rare earth elements was resolved through sequential evaporation at 80 degrees Celsius followed by microwave digestion. Digestion methods without using HClO₄ or H₃BO₃ and using only H₃BO₃ were unsuitable due to lower recoveries and higher procedural blanks, respectively. Digestion methods that involved the use of HCl-HNO₃-HF and HCl-HNO₃-HF-HClO₄ were most suitable, resulting in better recoveries of the elements. However, the HCl-HNO₃-HF method was preferred compared to HCl-HNO₃-HF-HClO₄ because the former avoids the use of HClO₄ and thus was used in measurements of the radiogenic isotopes of Sr and Nd. The optimized method was used to verify the reference values for the isotopic compositions of Sr and Nd in geological standard reference materials.     

Determination of k 0-factors and validation of k 0-INAA for short-lived nuclides

For standardization of k ₀-based instrumental neutron activation analysis, k ₀-factors for short-lived nuclides (half-lives—11 s to 37 min) of elements F, Se, Sc, Al, V, Ti, Cu, Ca, Mg, I, and Cl with respect to gold (¹⁹⁷Au) were determined using pneumatic carrier facility (PCF) at CIRUS reactor of BARC, Mumbai. Characterization of PCF was carried out by cadmium-ratio method using Au and Zr. The experimental k ₀-factors of the isotopes were found to be in good agreement with the recommended k ₀-factors in most of the cases, as evident from the values of % error and U-score at 95% confidence level. The method was validated by determining concentrations of elements through their short-lived nuclides in one type of the synthetic multielement standards (SMELS-I) obtained from SCK-CEN, Belgium. The method was also applied for determination of concentrations of some of the elements in two reference materials of IAEA, SL-3, and SL-1.     

Slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry for the determination of Cr, Cd and Pb in plastics

Ultrasonic slurry sampling electrothermal vaporization dynamic reaction cell inductively coupled plasma mass spectrometry (USS–ETV–DRC–ICP–MS) for the determination of Cr, Cd and Pb in several plastic samples, using NH₄NO₃ as the modifier, is described. The influences of the instrumental operating conditions and the slurry preparation technique on the ion signals are investigated. A reduction in the intensity of the background at signals corresponding to chromium masses (arising from matrix elements) was achieved by using NH₃ as the reaction cell gas in the DRC. The method was applied to determine Cr, Cd and Pb in two polystyrene (PS) samples and a polyvinyl chloride (PVC) sample using two different calibration methods, namely standard addition and isotope dilution. The results were in good agreement with those for digested samples analyzed by ultrasonic nebulization DRC–ICP–MS. The precision between sample replicates was better than 17% with the USS–ETV–DRC–ICP–MS method. The method detection limits, estimated from standard addition curves, were about 6–9, 1–2 and 8–11 ng g⁻¹ for Cr, Cd and Pb, respectively, in the original plastic samples.     

k0-Instrumental Neutron Activation Analysis Establishment at CDTN, Brazil: A successful story

Since 1995 the k ₀ instrumental neutron activation analysis has been applied at Radiochemical Laboratory, CDTN/CNEN, Brazil, by means of TRIGA MARK I IPR-R1 research reactor. At that time , f, and T _n were determined and the most recent determination of these parameters confirmed the great stability of the reactor along these years. In order to verify the efficiency and accuracy of the method, several certified reference materials have been systematically analyzed. Participating in Intercomparison Exercises organized by IAEA has been an important, essential and useful procedure to quality control. CDTN is the only Brazilian Institute to apply the k ₀-INAA to determine elements by means of their isotopes through short, medium and long half life using its own nuclear reactor.     

Element profiles of onion producing districts in Japan, as determined using INAA and PGA

We carried out instrumental neutron activation analysis (INAA) as well as k ₀-based prompt gamma-ray analysis (k ₀-PGA) to measure the amount of the elements in onions and studied whether the onions collected from different sites can be categorized based on the elemental concentration profile. Six elements (Na, Mg, Cl, K, Ca, Mn) and 3 elements (B, S, Cl) were measured by INAA and PGA in the onions grown in two districts, Hokkaido and Saga, in Japan, respectively. After principal component analysis, it was found that Cl was an important element to feature the producing districts of onions.     

Application of the INAA methods for KRISS infant formula CRM analysis: standardization of INAA at KRISS

We have established an instrumental neutron activation analysis (INAA) method, including k₀-based INAA, at the Korea Research Institute of Standards and Science (KRISS) for the certification of reference materials. As part of establishing INAA measurements, KRISS infant formula certified reference material was analysed for multiple elements at three different metrological institutes: KRISS and NIST for the standard comparator method, and JSI for the k₀-INAA method. The mass fraction of most elements was consistent within expanded uncertainty (k?=?2). In addition, the results were used to verify the validity of elemental analysis of Zn using the standard comparator INAA at KRISS, and spreadsheet-based INAA calculations were evaluated.

     

Multi-element analysis of soil from the north-western region of India by neutron activation analysis using the single comparator method with special reference to selenium toxicity

The single comparator (k₀) instrumental neutron activation analysis (INAA) was employed to determine the elemental composition of soil from the north-western region of India. The radiometric assay was carried out using high resolution gamma-ray spectrometry. Seventeen elements were detected including selenium whose concentration was found to be in the range of 1.02 to 6.79 mg/g.     

Separation of uranium from uraniferous coaly clays using a selective ion-exchange two-step elution system

Summary An ion-exchange process for the selective separation and enrichment of uranium from the main elements Si, Al, Fe, Ca, Mg, Na, K as well as from Mo and V, which are present in uraniferous coaly clays, has been developed. After a selective carbonate leaching of the roasted ore, a 0.5 mol/l Na₂CO₃/0.5 mol/l NaHCO₃ solution was passed through the macroporous ion-exchanger AG MP-1, which at pH10 absorbed uranium quantitatively in form of a carbonato complex. Remaining absorbed amounts of Mo and V were eluted with 0.1 mol/l EDTA in 0.5 mol/l Na₂CO₃/0.5 mol/l NaHCO₃, while U was quantitatively separated by a second elution step with 0.5 mol/l HNO₃ and was afterwards precipitated with NH₄OH as a high-grade yellow cake. Differential pulse polarography (DPP), atomic absorption spectroscopy (AAS), X-ray fluorescence (XRF), instrumental neutron activation analysis (INAA) and inductively coupled plasma mass spectrometry (ICP-MS) had been used to determine the uranium content in the raw materials and to investigate the effectivity of the different steps of the developed process.     

Major and trace element assessment of Tietê river sediments, São Paulo, Brazil

The objective of this study was to quantify major and trace elements present in sediments collected from the one of Brazil’s most important rivers, Tietê River. Sediments from 5 different sampling points (P₀–P₄), in 3 campaigns (2008/2009), from the headwaters to Suzano County upstream from São Paulo city were collected. X-ray fluorescence was applied for measuring total concentration of major elements and instrumental neutron activation analysis (INAA) for trace elements. The elements Cd, Hg and Pb were determined by atomic absorption spectrometry after digestion using the US EPA 3,051 procedure. These metal concentrations were compared to the PEL and TEL oriented values from CCME. The sampling sites P₃ and P₄, near industrialized areas, showed the highest concentrations for potentially bioavailable metals, mainly Pb and Hg. The results obtained by INAA were compared to upper continental crust values. A strong enrichment was found for the elements As, Br, Sb, Th, U and Zn. These results evidenced contamination by industrial effluents and sewage even relatively close to the Tietê River headwaters. The worst biological effects (acute toxicity) on benthonic organism Hyalella azteca were also observed at P₃ and P₄.     

ICP-OES法快速测定华阳川铀多金属矿中铌和铅

采用氢氟酸-硝酸-高氯酸体系对华阳川铀多金属矿进行高温消解,并对消解条件进行优化。使用电感耦合高频等离子体原子发射光谱仪(ICP-OES),在最佳仪器条件下,对华阳川铀多金属矿中铌元素和铅元素进行检测。结果表明,方法线性相关系数为分别为0.9998和0.9999,两种元素在标准样品中的加标回收率在96.0% ~104% 之间,平行样的相对标准偏差约0.50%~3.32%。实际样品加标回收率约为96.1 % ~ 102 %。该分析测试方法可以对华阳川铀多金属矿中铌铅元素进行快速、准确的测定。     

The determination of boron in zirconium and zircaloy by proton activation analysis based on the 10B(p, α)7Be reaction

The determination of boron in zirconium and zircaloy based on the ¹⁰B(p, α)⁷Be reaction is described. At the 100 and 20 μg g^-1 concentration level (doped samples), instrumental analysis is feasible. At lower concentrations, ⁷Be is separated from the activities formed from zirconium and its alloying elements or impurities, by anion-exchange in hydrofluoric acid medium followed by precipitation of YF₃ and of BaBeF₄. The chemical yield of the separation was determined in several ways. The sensitivity of the method was 15 ng g^-1. For concentrations ranging from 100 to 0.15 μg g^-1, the precision ranged from 3.5 to 10.7%. The results are compared with results obtained by other methods.     

Application of k0-method in instrumental neutron activation analysis to glass matrix: test study for low power research reactor GHARR-1

In this work k₀-INAA (via IAEAk₀-software) has been applied on glass samples to determine major, minor and trace element concentration. As many as 50 elements were detected and quantified with 3–5 mg of 0.1 % AuAl comparator monitor (0.1 % gold–99.9 %Alumimum wire). The average concentration of SiO₂, Na₂O, CaO, Al₂O₃ and MgO ranged between 76–96 %, 11.15–12.66 %, 5.26–10.71 %, 1.13–2.73 % and 3.51–6.23 % respectively. The relative concentrations of impurity elements; Cr, Fe, Mn and Co determined from the glass samples were used to match the physical appearance (color) of the glass based on general knowledge of colored glass production. The analytical procedure was validated using SRM 610 (glass matrix) and SRM GBW07106 (rock matrix) both as control samples which indicated a relative uncertainty of 15 and 6 % respectively for SRM 610 and SRM GBW07106. The relative sensitivity at which some of the elements were detected in major, minor and trace levels have indicated, that the k₀-method in instrumental neutron activation analysis using low power research reactor is a useful technique in glass analysis and could equally be used for forensic and archeological glass characterization.     

Elemental analysis of topaz from northern areas of Pakistan and assessment of induced radioactivity level after neutron irradiation for color induction

To study the impurity elements, which render color-induced topaz long lived radionuclides, three samples of topaz, from three different cities of the Northern Pakistan (Baltistan, Gilgit and Mardan) were analyzed using k ₀ instrumental neutron activation analysis (k ₀-INAA). The samples were irradiated in Pakistan Research Reactor-1 (PARR-1) and PARR-2 at Pakistan Institute of Nuclear Science & Technology (PINSTECH), Islamabad. The method was validated by analyzing IAEA-S7 reference material. In three samples a total of 22 trace level impurity elements were quantified. Among impurities, 10 elements including As, Ce, Ga, Ge, La, Na, Sb, Sc, U and Zn were common in topaz of all the three places. The storage time has been calculated for each sample required to bring the induced radioactivity down to permissible level given by US National Regulatory Commission.     

Determination of uranium, thorium, and 20 other elements in high-purity tungsten by radiochemical neutron activation analysis

A radiochemical neutron activation analysis method for the determination of 22 elements in high-purity tungsten has been developed. For the assay of indicator radionuclides with long half-lives, the radiochemical separation was performed from HF/H₂O₂, HF/NH₄F and HCl/H₂SO₄ media by a combination of cation and anion exchange on a Dowex 50 W × 8 and Dowex 1 × 8 column. An effective removal of the matrix-produced radionuclides of W and Re was achieved. U was determined via ¹⁴⁰La, the daughter nuclide of the fission product ¹⁴⁰Ba. Limits of detection of 2 ng/g for U and 0.02 ng/g for Th can be achieved. For the other elements, the limits of detection are between 0.004 ng/g (Sc) and 200 ng/g (Sr). The elements Hf, Ta and Sb could be determined by instrumental neutron activation analysis. This method was applied to the analysis of two tungsten powder samples of different purity grade. The results and limits of detection are compared with those of other methods.     

Determination of some trace elements in the industrial process of aluminium production

Some trace elements in samples from the aluminium industry (Aluminium Kombinat, Titograd, Yugoslavia) were determined by instrumental neutron activation analysis. Samples characteristic for alumina production (bauxite, red sludge), reduction cell components (alumina, anode, AlF₃, cryolite) and aluminium produced (purity 99.5–99.7%) have been analyzed. 10 trace elements were determined under a given set of working conditions and followed through the routine production.