Inter-method comparison for the determination of antimony and arsenic in peat samples

Four analytical approaches, based on different physical principles, for the determination of antimony (Sb) and arsenic (As) in ancient peat samples were critically evaluated: (a) open vessel digestion/hydride generation-atomic absorption spectrometry (HG-AAS), (b) closed-pressurized digestion in a microwave oven followed by sector field-inductively coupled plasma-mass spectrometry (SF-ICP-MS), (c) digestion in a microwave autoclave and subsequent quadrupole-inductively coupled plasma-mass spectrometry (Q-ICP-MS) measurements and (d) instrumental neutron activation analysis (INAA). The quality control scheme applied, always included the use of adequate plant reference materials to ensure the accuracy and precision of the analytical procedures. Additionally, two internal peat reference materials were analyzed using all four analytical approaches, generally showing good agreement for both elements. Method detection limits for As and Sb provided by all procedures were approximately 5 and 2 ng g⁻¹ which is sufficiently low for the reliable quantification of both elements in ancient, pre-anthropogenic peat samples. A comparison of As and Sb concentrations in a set of peat samples determined by INAA, HG-AAS and SF-ICP-MS revealed that INAA underestimated the values in a systematic manner, whereas HG-AAS and SF-ICP-MS data agreed very well. Best precision of the results was obtained by analytical procedures involving HG-AAS or Q-ICP-MS and varied from 3.6 to 4.3% and 7.1 to 7.5% for As (at about 0.5 μg g⁻¹) and Sb (at about 0.1 μg g⁻¹), respectively. The highest sample throughput (40 samples per run accomplished in 2 h) combined with low risk of sample contamination could be realized in the high-pressure microwave autoclave. The amount of sample required by all approaches was 200 mg, except for INAA which needed at least 25 times more sample mass to achieve comparable detection limits. For the quantification of As and Sb, inductively coupled plasma-mass spectrometry (ICP-MS) was preferred over INAA and HG-AAS, mainly because (a) less sample is needed and (b) As and Sb can be determined simultaneously. In addition, ICP-MS offers the possibility to measure concurrently a wide range of other elements which also are of environmental interest.     

Study on the retention of uranyl ions on modified clays with titanium oxide

Four analytical techniques—instrumental neutron activation analysis (INAA), inductively coupled plasma mass spectrometry (ICP-MS), scanning electron microscope energy dispersive X-ray fluorescence (SEM-EDXRF), and proton induced X-ray emission (PIXE)—were evaluated in the context of air pollution biomonitoring studies. Three combinations INAA/ICP-MS, ICP-MS/PIXE and ICP-MS/SEM-EDXRF are illustrated by experimental results.     

Determination of Elements in Japanese Standard Soil Materials by Means of Insturmental Neutron Activation Analysis

Instrumental neutron activation analysis (INAA), and inductively coupled plasma mass spectroscopy (ICP-MS) were applied to the determination of major elements and rare earth elements in Japanese Standard Soil Materials (NDG-1 to -8). Eight major elements, Al, Fe, Ti, Ca, Mg, Mn, K, and Na were determined by INAA. A comparison of the data for rare earth elements obtained by INAA and ICP-MS shows that the data of the contents determined by the two different analytical methods are in fairly good agreement with each other.     

Sequential multielement analysis of a single aerosol filter by different instrumental and wet-chemical methods

Summary The direct instrumental methods X-ray fluorescence spectrometry (XRFS) and instrumental neutron activation analysis (INAA), and, after digestion of the sample, inductively coupled plasma mass spectrometry (ICP-MS) were applied in sequence to analyse small single aerosol filters. XRFS detected up to 19, INAA up to 22, and ICP-MS up to 33 elements. In total, up to 45 elements were determined, and, for a number of additional elements limits of detection could be given. For many elements, the data quality could be checked by cross-comparison of the results of two or all three methods. These methods very meaningfully complement each other and, in the manner used, allow the determination of all elements of interest in a small aerosol filter sample.     

Unique quality assurance aspects of INAA for reference material homogeneity and certification

Summary Instrumental neutron activation analysis (INAA) has become one of the primary analytical techniques for certification of elemental content in biological Standard Reference Materials (SRMs) at the National Institute of Standards and Technology (NIST). One important reason why INAA has become so widely used and valuable in the certification of NIST SRMs is that INAA has unique inherent quality assurance (QA) characteristics which provide the capability for accurate analysis and which often allow the analytical values obtained to be internally evaluated and cross checked. While the NAA technique has the general characteristics of most spectroscopic techniques, the specific characteristics include uniform activation, long and well-documented excited states, highly penetrating emitted radiation, and an excited state decay process which is statistically random in nature. These characteristics work together to provide an analytical technique which can provide highly reliable analytical results and is particularly suitable for the certification of major, minor, and trace elements in biological reference materials.     

Trace element analysis of turkey vulture (Cathartes aura) feathers

Ten feather samples, including primary and secondary flight and tail feathers, were analysed for the trace element composition of vane and rachis structures using instrumental neutron activation analysis (INAA), inductively coupled plasma-mass spectrometry (ICP-MS), and cold vapour atomic absorption spectroscopy (CVAAS). Five environmentally significant elements, Cr, As, Se, Sb and Hg, were analysed by INAA and ICP-MS/CVAAS. A further seventeen elements were analysed by ICP-MS. The majority data obtained by INAA and ICP-MS/CVAAS were not statistically significantly different (p = 0.05), although the removal of isobaric interferences using dynamic reaction cell technology was essential to produce ICP-MS data that were consistent with INAA for Cr, As and Se. Significantly higher trace element concentrations were observed for vane relative to rachis for all elements, except Cu and Hg. These elements displayed vane/rachis ratios of 0.7 ± 0.2 and 1.0 ± 0.2, respectively. In general, vane and rachis subgroups afforded data that were consistent with a normal distribution, with RSDs in the range (12–83) % for INAA analyses. A total of 18 outliers were noted amongst the various feather, structure, element combinations, with 14 outliers being observed in the vane and/or rachis structures of the same tail feather. Given the significant differences in vane and rachis concentrations observed for many elements, the large RSDs reported for elements and the potential for outliers, the determination of environmental trace element burden using feathers is significantly enhanced by the analysis of multiple feathers using INAA.     

Determination of trace impurities in electronic grade quartz: Comparison of inductively coupled plasma mass spectroscopy with other analytical techniques

An analytical procedure for the determination of uranium and thorium in the sub-ng/g range as well as of other trace elements in the ng/g to g/g range in high purity quartz samples is described. The results obtained by inductively coupled plasma mass spectroscopy (ICP-MS) are compared to those obtained by other analytical techniques (instrumental neutron activation analysis, INAA; flame atomic absorption spectrometry, AAS; Zeeman graphite furnace atomic absorption spectrometry, ZGFAAS; total reflection X-ray fluorescence analysis, TRFA; direct current arc optical emission spectrometry, DC-arc OES; and X-ray fluorescence analysis, XRFA). For the ICP-MS measurements, the decomposition of the samples is carried out with HF/HNO₃/H₂SO₄-mixtures. The results obtained by the different methods show reasonable agreement. For uranium and thorium, ICP-MS proves to be the most sensitive method: detection limits of about 50 pg/g can be achieved for both elements.Presented in part at the 1989 European Winter Conference on Plasma Spectrochemistry, Reutte, Austria     

Use of neutron activation analysis and LC–ICP-MS in the development of candidate reference materials for As species determination

Arsenic (As) is widely found in marine organisms, mainly as organic arsenical compounds. With the introduction of regulations for As species in foodstuffs and for environmental control, it has become more important to quantify the amount of arsenic species present. To address this concern new reference materials (RMs) for validation and quality assurance of As speciation measurements are being developed, including a tuna fish tissue and a robalo liver tissue. Instrumental neutron activation analysis (INAA) is used in this work as a proven analytical tool for As determinations and for validating the As mass fraction determined by liquid chromatography coupled to inductively coupled mass spectrometry (LC–ICP-MS) in extracts of the candidate RMs and other fish samples including certified RMs. Various methods for the extraction of water-soluble As species were evaluated. The best results were acquired after methanol/acetone/water extraction yielding in 93 % extractable As in the tuna RM. This procedure was used for the LC–ICP-MS studies. The results demonstrate that INAA can account for 100 % of the distribution of As species in analytical processes. It complements LC–ICP-MS for the validation of the characterization of As species in the development of RMs for such species. Excellent agreement of measured results in certified RMs with the reported values confirms the validity of the applied procedures.     

Nuclear analytical techniques for quantification of uranium for its recovery from seawater

Nuclear analytical techniques namely fission track technique using solid state nuclear track detector (SSNTD) and instrumental neutron activation analysis (INAA) have been standardized and applied for quantification of low uranium concentrations in liquid samples such as feed, elute and brine and solid sorbent samples respectively. The quantification of uranium is required for its recovery study from seawater, which is one of the potential sources of uranium. The uranium concentration of a liquid sample obtained by SSNTD method was compared with the other well established conventional techniques like ICP-MS, ICP-AES, adsorptive stripping voltametry and alpha spectrometry. INAA was applied for uranium concentration determination in the radiation grafted polyamidoxime sorbent samples.     

Characterization of geomaterials from NE Portugal using k 0-based instrumental neutron activation analysis (k 0-INAA) and gamma spectrometry methods

The main objective of this study is the elemental characterization of geomaterial samples (??soils?? and Ra?as), collected between 2007 and 2008, in the Morais Massif, (NE Mainland of Portugal) by using two complementary techniques: instrumental neutron activation analysis (INAA) and high resolution gamma spectrometry. Samples granulometric fractions lower than 63???m were analyzed by gamma spectrometry, for artificial and natural radionuclides using HPGe detectors and by INAA, for chemical elements at the Portuguese research reactor, RPI. Statistical analysis, such as clusters analysis and Pearson correlations were applied to the obtained results. The enrichment factors were also calculated as an estimator of anthropogenic inputs in relation to the average crustal abundance. Group differentiation of Ra?as and ??soils?? is clearly shown from cluster analysis. The strong correlation factors obtained between some chemical elements corroborates the origins and the geology/mineralogy of the area studied. The combined application of both nuclear analytical techniques has shown their importance in providing useful information for the future site and repository performance and safety assessment studies.     

Instrumental Neutron Activation Analysis (INAA) and Inductively Coupled Plasma/Mass Spectrometry (ICP-MS) for Trace Element Biomonitoring using Mosses

Two analytical methods - instrumental neutron activation analysis (INAA) and inductively coupled plasma mass spectrometry (ICP-MS) - were used for the trace element analysis of naturally growing mosses for a heavy metal biomonitoring survey. The techniques were applied to reference mosses to evaluate the feasibility, analytical variability, detection limits and accuracy. These parameters were evaluated using 563 mosses sampled in the 1996 French survey. All the elements of interest in the European program "Atmospheric Heavy Metal Deposition in Europe - estimation based on moss analysis" (As, Cd, Cr, Cu, Fe, Hg, Pb, Ni, V, Zn) were able to be determined by ICP-MS. INAA appeared suitable for the determination of As, Cr, Fe, Hg, V and Zn. The Cd, Cu, Ni and Pb concentrations determined by ICP-MS were preferred to the INAA results, because of increased feasibility or accuracy. The results provided by both methods on the French mosses were statistically compared for 14 elements. Significant linear correlation appeared for: Ba, Ce, Cs, La, Rb, Sm, Th and V. Among these eight elements, Ba, Cs, La and Sm concentrations determined by both methods exhibited a strong statistical similarity. The correlations obtained for As, Eu, Fe and Sb were not as strong and no correlation at all was observed for Co and Cr. These differences were attributed to instrumental factors (e.g. spectral interference occurred for both methods) or due to the sample preparation prior to ICP-MS. The consequences of such results on the regional trend evaluation of atmospheric heavy metal deposition were discussed.     

Multielement analytical procedure coupling INAA, ICP-MS and ICP-AES: Application to the determination of major and trace elements in sediment samples of the Bouregreg river (Morocco)

Instrumental neutron activation analysis (INAA), inductively coupled plasma-mass spectrometry (ICP-MS) and inductively coupled plasma-atomic emission spectrometry (ICP-AES) were used for the determination of major and trace elements in sediment samples of the Bouregreg river (Morocco). The reliability of the results was checked, by using IAEA Soil-7 certified reference material. Results obtained by the three techniques were compared to control digestions efficiencies. A general good agreement was found between INAA and both ICP-MS and ICP-AES after alkaline fusion (ICPf). The ICP-MS technique used after acid attack (ICPa) was satisfactory for a few elements. A principal component analysis (PCA) has been used for analyzing the variability of concentrations, and defining the most influential sites with respect to the general variation trends. Three groups of elements could be distinguished. For these groups a normalization of concentrations to the central element concentration (that means Mn, Si or Al) is proposed.     

A computer-controlled direct sample insertion device for inductively coupled plasma-mass spectrometry

A direct sample insertion (DSI) device has been developed for application to inductively coupled plasma-mass spectrometry (ICP-MS). In a DSI device for use with ICPs, the sample is placed into or onto a probe with subsequent introduction of the sample carrying probe, via the central tube of the ICP torch, into the plasma. A mechanical, stepper-motor driven, computer controlled DSI device and software support system has been designed and developed that can easily be attached to a commercial ICP-MS system (Perkin-Elmer/SClEX Elan). This system allows the direct introduction of microliter volumes of liquids and milligram quantities of powdered/solid samples into the ICP-MS with little or no sample pre-treatment.     

Multi-element determination in earthworms with instrumental neutron activation analysis and inductively coupled plasma mass spectrometry: A comparison

Earthworms were collected from agricultural fields in Admont, Graz, Piber and Gumpenstein, Austria. Six earthworm samples were investigated with INAA and with ICP-MS in parallel for the element concentrations of As, Ba, Cd, Co, Cr, Cu, Fe, Hg, Pb, Rb, Sb, Se and Zn. With both techniques 14 elements were analysed in a wide concentration range (ng/g to mg/g) GF-AAS and HG-AAS were used for verification of some element concentrations. A comparison of analytical results between INAA and ICP-MS was discussed. In general, good agreement between ICP-MS and INAA was obtained, the relative difference values of most of the elements are within ±20% range, however, a methodical error for the determination of Hg by ICP-MS was found.     

A novel sample decomposition technique at atmospheric pressure for the determination of Os abundances in iron meteorites using isotope dilution inductively coupled plasma-mass spectrometry.

A safe and reliable analytical technique for the determination of Os abundances in ten iron meteorites of various chemical groups was developed using isotope dilution inductively coupled plasma-mass spectrometry coupled with a sample decomposition technique. A major advantage of the sample decomposition technique developed here is that the pressure inside the reaction flask is not increased through the decomposition reaction because the flask is a fully opened system, obviating the risk of explosion of the glass apparatus. Another advantage is that there is no restriction in the sample size being decomposed. In this study, about 2 g of metallic sample were decomposed safely, and this sample size, > 10 times larger than that typically used for the Carius tube technique, allows one to obtain more reliable Os data for heterogeneous samples. The metallic samples were decomposed in a glass flask purged with Ar. Since the O2 was purged from the reaction flask, Os was not oxidised to volatile OsO4, thereby preventing significant evaporation loss of Os. The typical recovery of Os throughout the sample decomposition and separation processes was > 80%, and the total Os blank through the decomposition of a 1 g amount of sample was less than 20 pg. Os abundances were determined by means of stable isotope dilution mass spectrometry using a 190Os-enriched isotopic tracer. Except for Sikhote-Alin, the measured Os abundances in almost all the iron meteorites exhibited a good agreement with the previously published Os abundance data, within the analytical uncertainty achieved in this study (2-5%). For the Sikhote-Alin meteorite, on the basis of a better correlation between Os and Ir abundances, we believe that our Os abundance data should be more reliable. The Os abundance data obtained in this work clearly demonstrated the suitability of the newly developed sample decomposition procedure for low level Os determinations.     

Contribution of ICP-IDMS to the certification of antimony implanted in a silicon wafer - comparison with RBS and INAA results

A thin-layer reference material for surface and near-surface analytical methods was produced and certified. The surface density of the implanted Sb layer was determined by Rutherford backscattering spectrometry (RBS), instrumental neutron activation analysis (INAA), and inductively coupled plasma isotope dilution mass spectrometry (ICP-IDMS) equipped with a multi-collector. The isotopic abundances of Sb (121Sb and 123Sb) were determined by multi-collector ICP-MS and INAA. ICP-IDMS measurements are discussed in detail in this paper. All methods produced values traceable to the SI and are accompanied by a complete uncertainty budget. The homogeneity of the material was measured with RBS. From these measurements the standard uncertainty due to possible inhomogeneities was estimated to be less than 0.78% for fractions of the area increments down to 0.75 mm2 in size. Excellent agreement between the results of the three different methods was found. For the surface density of implanted Sb atoms the unweighted mean value of the means of four data sets is 4.81 x 10(16) cm(-2) with an expanded uncertainty (coverage factor k = 2) of 0.09 x 10(16) cm(-2). For the isotope amount ratio R (121Sb/123Sb) the unweighted mean value of the means of two data sets is 1.435 with an expanded uncertainty (coverage factor k = 2) of 0.006.     

Quality Control in Element Analysis of Plant Materials

A worldwide laboratory intercomparison was organized by the International Atomic Energy Agency's Analytical Quality Control Services (AQCS) involving the determination of elements in plant materials used for human consumption. The main purpose of this work was to evaluate the performance of our analytical methods including sample preparation and to obtain new reference materials that can be used in our further work. Both materials (spinach and cabbage) were analyzed by inductively coupled plasma atomic emission spectrometry (ICP-AES) and instrumental neutron activation analysis (INAA). Six subsamples of each material were subjected to our digestion procedure and the solutions were measured by ICP-AES. The dried samples were analyzed using INAA. Up to 26 elements were determined in plant materials. For easy review of our data a score has been calculated based on the reference value for each measured element. According to our results the ICP-AES technique was useful for determination of the following elements: Ba, Ca, Cr, Fe, K, Mn, Mo, P, S, Sr, Ti. The INAA method was reliable for measurement of Ce, Co, Mn, Na, Rb, Th, and V.     

Comparison of standard and reaction cell inductively coupled plasma mass spectrometry in the determination of chromium and selenium species by HPLC-ICP-MS

Elemental speciation is becoming a common analytical procedure for geochemical investigations. The various redox species of environmentally relevant metals can have vastly different biogeochemical properties, including sorption, solubility, bioavailability, and toxicity. The use of high performance liquid chromatography (HPLC) coupled to elemental specific detectors, such as inductively coupled plasma mass spectrometry (ICP-MS), has become one of the most important speciation methods employed. This is due to the separation versatility of HPLC and the sensitive and selective detection capabilities of ICP-MS. The current study compares standard mode ICP-MS to recently developed reaction cell (RC) ICP-MS, which has the ability to remove or reduce many common polyatomic interferences that can limit the ability of ICP-MS to quantitate certain analytes in complex matrices. Determination of chromium and selenium redox species is achieved using ion-exchange chromatography with elemental detection by standard and RC-ICP-MS, using various chromium and selenium isotopes. In this study, method performance and detection limits for the various permutations of the method (isotope monitored or ICP-MS detection mode) were found to be comparable and generally less than 1 μg L⁻¹. The method was tested on synthetic laboratory samples, surface water, groundwater, and municipal tap water matrices.     

Environmental application of elemental speciation analysis based on liquid or gas chromatography hyphenated to inductively coupled plasma mass spectrometry—A review

In recent years the number of environmental applications of elemental speciation analysis using inductively coupled plasma mass spectrometry (ICP-MS) as detector has increased significantly. The analytical characteristics, such as extremely low detection limits (LOD) for almost all elements, the wide linear range, the possibility for multi-elemental analysis and the possibility to apply isotope dilution mass spectrometry (IDMS) make ICP-MS an attractive tool for elemental speciation analysis. Two methodological approaches, i.e. the combination of ICP-MS with high performance liquid chromatography (HPLC) and gas chromatography (GC), dominate the field. Besides the investigation of metals and metalloids and their species (e.g. Sn, Hg, As), representing “classic” elements in environmental science, more recently other elements (e.g. P, S, Br, I) amenable to ICP-MS determination were addressed. In addition, the introduction of isotope dilution analysis and the development of isotopically labeled species-specific standards have contributed to the success of ICP-MS in the field. The aim of this review is to summarize these developments and to highlight recent trends in the environmental application of ICP-MS coupled to GC and HPLC.     

Application of instrumental neutron activation analysis and inductively coupled plasma-mass spectrometry to studying the river pollution in the State of Minas Gerais

Instrumental neutron activation analysis (INAA) and inductively coupled plasma-mass spectrometry (ICP-MS) have been used for the determination of toxic heavy metals and other pollutants in the water of the Das Velhas river in the State of Minas Gerais, in south-east Brazil. Elemental concentrations of about 60 elements were measured in water samples collected to different parts of this river and from two affluents. There was a good agreement between the two analytical methods and the results were complementary. The results indicated an increase in the concentration of several polluting elements in the water from mining industry area.