Geochemical Reference Samples Research Articles

Effect of soil moisture and its correction method for quantitative analysis of hazardous metals in polluted soil for the on‐site XRF analysis

We investigated the effects of soil moisture and its correction method for on‐site XRF analysis of hazardous metals in polluted soil. A wet soil sample was prepared by exposing the water mist generated from the ultrasonic humidifier to dry soil for 0–95 min to reach the soil water content to 0–30 mass%. Calibration curves of six hazardous metals (Cr, As, Se, Cd, Hg, and Pb) measured from the soil certified reference materials JSAC 0461 to 0466 were compared with the water content changed from 0 to 30 mass%. The inclinations of calibration curves of six metals decreased with the increase of the water content. In addition, the XRF intensities of six metals decreased about 15%–20% by adding the water in 30 mass%. It was revealed that the soil moisture effect is caused by two factors as a decrease of the amount of analyte in the XRF generating area, and a change in the sample matrix due to increase of water contents. Thus, a new correction method using the combination between Compton scattered X‐rays and the water contents was applied to overcome the soil moisture effect. Applying the proposed correction method, calibration curves of six metals with different water content gave identical inclinations of calibration curves. The analytical results of chromium in the geochemical reference sample were in good agreement with the standard value even with increased water content.

Precise analysis of antimony isotopic composition in geochemical materials by MC-ICP-MS

Antimony (Sb) isotopes have been shown to be promising tracers for studying Sb cycling in the environment and its impact on ecosystem and human health. Yet precise measurements of Sb isotopic composition have been challenged by low Sb concentrations and high matrix effect and by the lack of a common reference material (zero-delta). Here we report an improved analytical scheme that is capable of high-precision measurement of Sb isotopes in environmental and geochemical samples. The method employs a two-column ion exchange set-up to remove interfering matrix elements to allow Sb isotopic measurements with low Sb (< 0.15 μg/g) and high matrix content. The instrument mass bias is corrected by combining the sample-standard bracketing method with internal normalization of cadmium. To allow for interlaboratory comparisons, a standard reference material certified for the total Sb concentration, NIST SRM 3102a, is recommended as the reference standard (“zero-delta”) for Sb isotope measurements. The improved method is applied for high-precision and high-accuracy Sb isotope composition measurements in environmental and geochemical reference samples with a minimum Sb required per analysis as low as 3.0 ng. By expressing our data and previously reported literature data against the same reference standard (NIST SRM 3102a), we provide an update on isotopic compositions of various types of environmental, geological and anthropogenic materials. The improved analytical method and database aid further studies on the mechanisms of Sb isotope fractionation and its application as a tracer for the study of the sources, processes and fate of Sb in the environment.

SPX Flow Inc, USA

Antimony (Sb) isotopes have been shown to be promising tracers for studying Sb cycling in the environment and its impact on ecosystem and human health. Yet precise measurements of Sb isotopic composition have been challenged by low Sb concentrations and high matrix effect and by the lack of a common reference material (zero-delta). Here we report an improved analytical scheme that is capable of high-precision measurement of Sb isotopes in environmental and geochemical samples. The method employs a two-column ion exchange set-up to remove interfering matrix elements to allow Sb isotopic measurements with low Sb (< 0.15 μg/g) and high matrix content. The instrument mass bias is corrected by combining the sample-standard bracketing method with internal normalization of cadmium. To allow for interlaboratory comparisons, a standard reference material certified for the total Sb concentration, NIST SRM 3102a, is recommended as the reference standard (“zero-delta”) for Sb isotope measurements. The improved method is applied for high-precision and high-accuracy Sb isotope composition measurements in environmental and geochemical reference samples with a minimum Sb required per analysis as low as 3.0 ng. By expressing our data and previously reported literature data against the same reference standard (NIST SRM 3102a), we provide an update on isotopic compositions of various types of environmental, geological and anthropogenic materials. The improved analytical method and database aid further studies on the mechanisms of Sb isotope fractionation and its application as a tracer for the study of the sources, processes and fate of Sb in the environment.

X-ray fluorescence analysis of major and trace elements in silicate rocks using 1:5 dilution glass beads

Thisreport describes analytical techniques for major and trace elements in silicate rocks by X-ray fluorescence (XRF) spectrometry. The analyzed elements are SiOz, Ti02, A1203, total Fe203, MnO, MgO, CaO, Na20, K20, P2Os, Sc, V, Cr, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, La, Ce, Nd and Pb. All of these elements were determined on a single glass bead made from mixtures of 1 g of sample powder, 5 g of Li2B407 flux and about 50 mg of Lil releasing agent. A series of synthetic standard samples were prepared from pure chemical reagents to calibrate an XRF spectrometer. Matrix and line overlap corrections using a fundamental parameter approach yields reliable calibration lines with wide optimal ranges of composition. Analytical results of GSJ geochemical reference samples are in good agreement with their recommended values and exhibit sufficient precision and sensitivity for both major and trace elements.

Simultaneous determination of chlorine and sulfur in geochemical reference samples by wavelength dispersive X-ray fluorescence spectrometry

Study on spectral line shifts and matrix effects of different inorganic sulfur species and geochemical reference samples by WD-XRF.

Caesium desorption from layer silicate minerals using quaternary ammonium salts

ABSTRACTThe adsorption and desorption of cesium onto layered minerals, zeolite and geochemical reference samples were studied. 0.5 g of bentonite and mica were able to adsorb 71.2 and 51.5 mg of cesium, respectively, from 50 mL of deionized water containing 200 mg/L of cesium under neutral pH condition. These amounts of cesium adsorption were greater than those reported for vermiculites (8.9 and 5.6 mg, respectively). Additionally, the cesium adsorption on mica and vermiculite remained essentially unchanged under seawater conditions, but it decreased drastically on zeolite. The cesium desorption from the layered minerals was promoted by the addition of ammonium ions, namely trioctylmethylammonium chloride and zephiramine. These ammonium ions desorb cesium from the interlayers of the minerals without destroying the mineral structure. The cesium desorption procedure using quaternary ammonium ions would be extremely useful for decontamination of soil containing the layered minerals with adsorbed radioactive cesium.

Potential Influence of Ocean Acidification on Deep-Sea Fe–Mn Nodules and Pelagic Clays: An Improved Assessment by Using Artificial Seawater

In order to assess the potential risk of metal release from deep-sea sediments in response to pH decrease in seawater, the mobility of elements from ferromanganese (Fe–Mn) nodules and pelagic clays was examined. Two geochemical reference samples (JMn-1 and JMS-2) were reacted with the pH-controlled artificial seawater (ASW) using a CO2-induced pH regulation system. Our experiments demonstrated that deep-sea sediments have weak buffer capacities by acid–base dissociation of surface hydroxyl groups on metal oxides/oxyhydroxides and silicate minerals. Element concentrations in the ASW were mainly controlled by elemental speciation in the solid phase and sorption–desorption reaction between the charged solid surface and ion species in the ASW. These results indicated that the release of heavy metals such as Mn, Cu, Zn and Cd should be taken into consideration when assessing the influence of ocean acidification on deep-sea environment.

ICP質量分析計を用いた地球化学標準試料（岩石・海水・炭酸塩）のリチウム同位体比迅速分析

ICP質量分析計を用いた地球化学標準試料（岩石・海水・炭酸塩）のリチウム同位体比迅速分析

Determination of 10 major and 34 trace elements in 34 GSJ geochemical reference samples using femtosecond laser ablation ICP-MS

Determination of 10 major and 34 trace elements in 34 GSJ geochemical reference samples using femtosecond laser ablation ICP-MS

ICP-MS法を用いた地球化学的標準試料中のZn, Cd, In, Tl, Pb, Biの定量 (2)―堆積岩, 堆積物

ICP-MS法を用いた地球化学的標準試料中のZn, Cd, In, Tl, Pb, Biの定量 (2)―堆積岩, 堆積物

ICP-MS 法を用いた地球化学的標準試料中のZn, Cd, In, Tl, Pb, Bi の定量 (1)―火成岩

ICP-MS 法を用いた地球化学的標準試料中のZn, Cd, In, Tl, Pb, Bi の定量 (1)―火成岩

Exposure Experiments of Geochemical Reference Samples to CO2-satureted Seawater

We investigated interactions between geochemical reference samples and CO2-saturagted seawater. The experiments were made under normal temperature and atmospheric pressure. We used the reference samples of igneous rocks, sedimentary rocks, sediments and terrestrial soil, issued from the Geological Survey of Japan (AIST). Chemical parameters in the seawater reacted with rock/sediment samples were determined. The results of quantitative analysis of by ICP-AES showed that calcium was released from coral, dolomite and limestone due to the dissolution of calcium carbonate in seawater acidified by CO2. Significant changes of other elements were not detected for all samples. The results of nutrient analysis showed that phosphate was eluted from dolomite, slate, coastal marine sediment and pelagic marine sediment significantly. Significant concentration of nitrate and nitrite were not detected except in the seawater reacted with terrestrial soil. On the other hand, concentrations of ammonia increased in the seawater reacted with slate, coastal marine sediment, pelagic marine sediment and terrestrial soil. Dissolved inorganic carbon (DIC) and total alkalinity (TA) were clearly increased in the seawater reacted with coral, dolomite, limestone. As above, increases of calcium were also detected in these samples, suggesting dissolution of calcium carbonate to the seawater acidified by CO2. Increase of DIC and TA in the coral sample are corresponded to the changes of partial pressure of CO2 (pCO2) in the seawater from 83% to 49% and pH from 4.8 to 6.1.

Sequential anion-exchange separation of trace U, Th, Pb and lanthanides in environmental samples

Abstract The sequential separation technique of U, Th, Pb, and the lanthanides with a single anion-exchange column was applied to analysis of the geochemical reference sample, JB-1. The separation technique was previously developed by the authors and reported. The sample was digested and dissolved in nitric acid. Five solutions of different volume containing 0.1–1 mg of the JB-1 were loaded on the separate columns, and the elements of interest in the solution were sequentially separated. The concentrations of the elements were measured with an ICP-MS. The elements were successfully separated and alkaline metals and alkaline earth metals were effectively eliminated from the elements. The elemental concentrations were concordant with the literature values within the deviation except for that of Th. The elemental concentrations were accurately determined in ≥500 μg of the JB-1 without subtraction of processing blanks.

The development of whole rock analysis of major and trace elements in XRF glass beads by fsLA-ICPMS in GSJ geochemical reference samples

Using laser-ablation inductively coupled plasma mass spectrometer (LA-ICPMS), we have improved the reliability of the abundance data for trace-elements in geochemical samples using a glass bead ablation method. The glass beads were made of mixture of 0.1 g sample and 1.0 g of lithium-tetraborate preliminary prepared for an analysis of major components using a X-ray fluorescence (XRF) technique. The present method has several advantages: 1) higher sensitivity than that achieved by the XRF method, 2) obviation of erroneous measurements due to incomplete dissolution of heavy minerals, and 3) simple, rapid and user friendly sample preparation procedures for the analysis of both the major and trace elements. Development of this method constitute: 1) femtosecond laser-ablation for minimal elemental fractionation during the laser ablation, 2) new software to control all the laser, sample stage movement as well as triggering the data acquisition using the ICP-MS, and 3) a newly designed sample cell to enhance the transport efficiency of the sample aerosol into the ICP. Moreover, to improve the data quality for both the major and trace elements, calibration lines were defined based on the Li-normalized signal intensities and the reported abundance values for the analytes in well distributed GSJ geochemical reference samples. These improvements enabled us to analyze whole-rock compositions at ≤100 sec/sample. Using this method, the precisions of analyses were better than 10% for Na, Mg, Al, Si, K, Ca, Sc, Ti, V, Mn, Co, Ga, Rb, Sr, Y, Zr, Nb, La, Pr and Nd; 20% for P, Zn, Sn, Ce, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, Th, and U, and 30% for Fe, Cs, Ba, and Eu. For Ni and As, precisions of the measurements was not better than 30%. Reliabilities of analyses were better than 10% for Na, Mg, Al, Si, K, Ca, Sc, Ti, V, Mn, Co, Rb, Sr, Y, Zr, Cs, Ba, La, Ce, Nd, Sm, Gd, Tb, Dy, Yb, Lu, Hf, Th and U; <20% for Zn, Ga, Nb, Sn, Pr, Sm, Eu, Ho, Er, Tm and Ta, and 30% for P. For Fe, Ni and As, reliability of the measurement was not better than 30%.

Determination of Fluoride Using ion-selective Electrodes in the Presence of Aluminum

We describe a method for determining fluoride with ion-selective electrodes (ISEs). Tartrate and Tris-based total ionic strength adjustment buffers (TISABs) were found to lower the interference from aluminum to a greater extent than conventional citrate-based TISABs. We adopted a solid TISAB addition method that is simple to perform, and can be carried out without lowering the level of fluoride. The apparent recovery of fluoride was 95% or higher, even at 500 mg L(-1) of Al3+ when a tartrate and Tris-based TISAB was used. Interferences from common ions were not observed at 100 mg L(-1) levels. We determined the fluoride content in solid silicate samples with ISEs without preliminary steam distillation after alkali fusion processing. Adding a solid TISAB mixture consisting of tartaric acid, sodium tartrate, and Tris, however, eliminated any interference from high levels of aluminum and sodium and potassium carbonates. The proposed analytical method was also applied to the determination of fluoride in geochemical reference samples.

Chemical Separation and Mass Spectrometry of Cr, Fe, Ni, Zn, and Cu in Terrestrial and Extraterrestrial Materials Using Thermal Ionization Mass Spectrometry

A sequential chemical separation technique for Cr, Fe, Ni, Zn, and Cu in terrestrial and extraterrestrial silicate rocks was developed for precise and accurate determination of elemental concentration by the isotope dilution method (ID). The technique uses a combination of cation-anion exchange chromatography and Eichrom nickel specific resin. The method was tested using a variety of matrixes including bulk meteorite (Allende), terrestrial peridotite (JP-1), and basalt (JB-1b). Concentrations of each element was determined by thermal ionization mass spectrometry (TIMS) using W filaments and a Si-B-Al type activator for Cr, Fe, Ni, and Zn and a Re filament and silicic acid-H3PO4 activator for Cu. The method can be used to precisely determine the concentrations of these elements in very small silicate samples, including meteorites, geochemical reference samples, and mineral standards for microprobe analysis. Furthermore, the Cr mass spectrometry procedure developed in this study can be extended to determine the isotopic ratios of 53Cr/52Cr and 54Cr/52Cr with precision of approximately 0.05epsilon and approximately 0.10epsilon (1epsilon = 0.01%), respectively, enabling cosmochemical applications such as high precision Mn-Cr chronology and investigation of nucleosynthetic isotopic anomalies in meteorites.

元素同時分析装置による地質標準試料中の炭素、水素、窒素および硫黄の定量

元素同時分析装置による地質標準試料中の炭素、水素、窒素および硫黄の定量

NEUTRON ACTIVATION ANALYSIS OF ARCHAEOLOGICAL MATERIALS: AN OVERVIEW OF THE ITN NAA LABORATORY, PORTUGAL

Instrumental neutron activation analysis (INAA) has been applied to archaeological samples at the Portuguese Research Reactor (RPI) since 1973, and the number of samples analysed has increased steadily since the mid‐1990s. Archaeometric applications of INAA at RPI include the analysis of archaeological ceramics and the stones used in monumental architecture (menhirs) and other historical monuments. A programme of analysis also exists for measuring the precision of and contributing to the certified values of geochemical reference samples. In addition, the study of interference factors is performed to obtain better accuracy in the determination of concentrations of some elements (e.g., corrections for spectral interferences from uranium fission products in the determination of barium, rare earth elements and zirconium).

Determination of Rare Earth Elements in Garnet Minerals, Geological Materials by Inductively Coupled Plasma–Atomic Emission Spectral and Mass Spectral Analysis

The performance of inductively coupled plasma–atomic emission spectrometry (ICP‐AES) for the determination of 14 lanthanides and Yttrium was evaluated by comparison with inductively coupled plasma–mass spectral (ICP‐MS) analysis. The geochemical reference samples (GRS), DNC‐1(diabase), AGV‐1(andesite), Sy‐2(syenite), MRG‐1(gabbro), AN‐G(anorthosite), AC‐E(granite), and MAG‐1(marine mud) were chosen as test materials and analyzed for checking the precision and reproducibility of the methods. The mineral garnet is separated from the black sands of the southwest coast of India, and the combined cation exchange–ICP method of AES analysis and MS analysis were carried out for the determination of rare earth elements. Both techniques are within the requirements needed for garnet minerals. The determination of rare‐earth elements in these minerals, which contain other elements as major contribution and trace distribution of rare‐earth elements, shows that ICP applied under the proper working condition lives up to the expectations. Major element analysis gives the formula of garnet of Manavalakurichi (MK) as (FeCaMg)2.79Al2.07Si3.05O12 approximated to Fe3Al2Si3O12, hence of almandine-type garnet. The enrichment of heavy lanthanides compared to the light lanthanides indicates that these lanthanides occupy the coordinaton site of Fe2+ by replacement. Both techniques are excellent in determining the very low concentration of lanthanides in geological materials, specifically garnet.

Mobility of lanthanides accompanying the formation of alunite group minerals

Concentration of lanthanides (Lns) in alunite group mineral samples from the Kusatsu-Shirane volcano area, Gunma, Japan, were determined by neutron activation analysis. Their Ln abundance patterns showed enrichment of light Lns relative to their original rocks and GSJ geochemical reference samples of feldspars. It was found that the concentration of light Lns increased with increasing concentration of K and P. The positive correlation between the light Lns and P concentration suggested the formation of florencite, whereas the positive correlation between the concentration of light Lns and K may reflect the difference between the solubility of double salts of K and Ln sulfates of light Lns and heavy Lns, respectively.