Determination of Bromine and Iodine in Twenty-three Geochemical Reference Materials by ICP-MS

Trace amounts (from nanogram to microgram levels) of bromine and iodine were determined by inductively coupled plasma-mass spectrometry (ICP-MS) in twenty-three geochemical reference materials issued by the GSJ, USGS, IAEA etc. The pyrohydrolysis technique was used to separate bromine and iodine from samples analysed in the form of powder. The accuracy and precision of the experimental values were assessed by the comparative analysis of well established reference materials such as USGS AGV-1, BCR-1 and IGGE GBW07312. The measured values agreed well with reported values within a 10% error range. We also report reliable new data for these elements in these geochemical reference materials.     

Iodine Content of Some Geochemical Reference Samples

18 geoahenrical reference samples have been analysed for iodine using an automated photometric method. Few comparative values are available in the literature but of the six that are available four show good agreement with the data reported. In all but one case the values obtained are less than 0.3 ppm, the exception being a bauxite (B.C.S. 395) with 8.8 ppm I.     

加速器质谱129 I分析及其在环境、地质研究中的应用

文章简要介绍了我们研究组近3年在129 I加速器质谱应用和分析方法方面的部分研究结果。测定了核前黄土样品中129 I水平,为地质定年的探索奠定了一定的基础; 通过抽样分析检测了我国某核电站核环境安全的状况,结果表明当前它与大气沉降的本底水平一致,环境是安全可靠的; 建立了水样、土壤、植物等不同类型样品中碘的分离、制备以及129 I加速器质谱测试方法,尤其对无载体微量碘分离、制备和其中129 I测量进行了探索,解决了超痕量碘样品的制备难题; 此外,对实验用的试剂以及食用碘盐等进行了检验,示踪了不同来源的碘,为数据的可靠和问题的分析提供了保障。结果显示,129 I既是一个地质、环境示踪的有效工具,又具有定年的潜力和广阔的应用前景。     

THE DETERMINATION OF FLUORINE BY PROTON INDUCED GAMMA RAY EMISSION SPECTROMETRY (PIGE) IN EIGHTEEN CHINESE STANDARD REFERENCE SAMPLES OF STREAM SEDIMENTS, SOILS AND ROCKS: GSD 9-12, GSS 1-8 AND GSR 1-6

Eighteen new Chinese standard reference samples (including stream sediments, soils and rocks) have been analysed by an automated proton induced gamma ray emission (PIGE) method for fluorine. Results of determinations are reported and are generally in good agreement with the "usable values" previously published.     

Neutron Activation Analysis of Nine GSJ Sedimentary Rock Reference Samples

Nine rock reference samples "Sedimentary rock series" issued by the Geological Survey of Japan (GSJ) were analysed for up to 31 elements by neutron activation analysis (NAA); 14MeV-NAA for Si and Al, fission track method for U, radiochemical and instrumental NAA for rare-earth elements, and instrumental NAA for the remaining elements, with reactor neutrons for the latter three. The present results are compared with reported values.     

Instrumental Neutron Activation Analysis of Two French Geochemical Reference Samples - Basalt BR and Biotite Mica-Fe

Instrumental neutron activation analysis results for 20 trace elements (Sc, Cr, Co, Ni, Rb, Cs, Ba, La, Ce, Nd, Sm, Eu, Gd, Tb, Tm, Yb, Lu, Hf, Ta, Th) and for two major elements (Na and Fe) in two geochemical reference samples issued by the "Centre de Recherches Pétrographiques et Géochimiques" are reported and compared with available literature values. In general our results agree well with recommended or proposed values.     

1996 COMPILATION OF ANALYTICAL DATA ON NINE GSJ GEOCHEMICAL REFERENCE SAMPLES, "SEDIMENTARY ROCK SERIES"

Analytical data compiled on nine Geological Survey of Japan (GSJ) reference samples, "Sedimentary rock series" received by February 1996 are reported. After excluding outliers and examining critically the analytical procedures employed, the data were evaluated statistically. Recommended or preferable values for fifteen major and sixty minor and trace elements are proposed.     

Thermodynamic properties of organic iodine compounds

A critical evaluation has been made of the thermodynamic properties reported in the literature for 43 organic iodine compounds in the solid, liquid, or ideal gas state. These compounds include aliphatic, cyclic and aromatic iodides, iodophenols, iodocarboxylic acids, and acetyl and benzoyl iodides. The evaluation has been made on the basis of carbon number systematics and group additivity relations, which also allowed to provide estimates of the thermodynamic properties of those compounds for which no experimental data were available. Standard molal thermodynamic properties at 25 °C and 1 bar and heat capacity coefficients are reported for 13 crystalline, 29 liquid, and 39 ideal gas organic iodine compounds, which can be used to calculate the corresponding properties as a function of temperature and pressure. Values derived for the standard molal Gibbs energy of formation at 25 °C and 1 bar of these crystalline, liquid, and ideal gas organic iodine compounds have subsequently been combined with either solubility measurements or gas/water partition coefficients to obtain values for the standard partial molal Gibbs energies of formation at 25 °C and 1 bar of 32 aqueous organic iodine compounds. The thermodynamic properties of organic iodine compounds calculated in the present study can be used together with those for aqueous inorganic iodine species to predict the organic/inorganic speciation of iodine in marine sediments and petroleum systems, or in the near- and far-field of nuclear waste repositories.     

Molecular environment of iodine in naturally iodinated humic substances: Insight from X-ray absorption spectroscopy

The molecular environment of iodine in reference inorganic and organic compounds, and in dry humic and fulvic acids (HAs and FAs) extracted from subsurface and deep aquifers was probed by iodine L₃-edge X-ray absorption spectroscopy. The X-ray absorption near-edge structure (XANES) of iodine spectra from HAs and FAs resembled those of organic references and displayed structural features consistent with iodine forming covalent bonds with organic molecules. Simulation of XANES spectra by linear combination of reference spectra suggested the predominance of iodine forming covalent bonds to aromatic rings (aromatic-bound iodine). Comparison of extended X-ray absorption fine structure (EXAFS) spectra of reference and samples further showed that iodine was surrounded by carbon shells at distances comparables to those for references containing aromatic-bound iodine. Quantitative analysis of EXAFS spectra indicated that iodine was bound to about one carbon at a distance d (I-C) of 2.01(4)-2.04(9) Å, which was comparable to the distances observed for aromatic-bound iodine in references (1.99(1)-2.07(6) Å), and significantly shorter than that observed for aliphatic-bound iodine (2.15(2)-2.16(2) Å). These results are in agreement with previous conclusions from X-ray photoelectron spectroscopy and from electrospray ionization mass spectrometry. These results collectively suggest that the aromatic-bound iodine is stable in the various aquifers of this study.     

1998 Compilation of Analytical Data for Five GSJ Geochemical Reference Samples: The "Instrumental Analysis Series"

Analytical data for five GSJ (Geological Survey of Japan) reference samples, the "Instrumental analysis series" received by October 1998, are compiled. The data reported in publications and personal communications were evaluated statistically, taking into account the analytical method and sample preparation. Based on the selected available data, recommended and preferred values for fourteen major and fifty one minor and trace elements are proposed.     

Reference Samples of Rocks - The Search for "Best Values"

Because of the disparate data, reported in collaborative analyses of reference samples of rooks, various methods have been proposed for deriving "best values". This work compares those methods and several additional ones. Included are two simplified estimates of "mode" which yield values close to those of the Dominant Cluster and Gamma Transformation methods. An example is also cited of the hazards that may result from too superficial reading of raw data.     

Precise determination of uranium in rocks and minerals by neutron activation analysis using 133I fission product

A radiochemical neutron activation technique for uranium determination in rock and mineral samples is presented. The method is based on an alkaline fusion, a selective oxidation of iodine by a sodium-nitrite solution, followed by an iodine distillation technique for the isolation of the ¹³³I produced in fission. The outlined scheme is rapid, sensitive and reliable. Determination of uranium in U.S. Geological Survey standard rocks (G-1, W-1, G-2, BCR-1, AGV-1, GSP-1), C.R.P.G. Nancy geochemical standards (GA, GH, BR, Mica-Fe, Mica-Mg), C.A.A.S. reference syenite rocks (SY-1, SY-2, SY-3) and other analysed rock samples are reported. These results are compared with those obtained by other methods.     

Candoluminescence Emission Analysis of Cerium in Thirty-Six International Geochemical Reference Samples

Cerium has been determined in thirty-six international geochemical reference samples using candoluminescence emission analysis. Samples are fused with sodium peroxide in nickel crucibles and interfering elements are removed by an ion exchange technique.
Cerium values obtained in the present work generally lie within ranges reported in the literature or close to the upper or lower ends of these ranges. Candoluminescence values for cerium compare favourably with previously reported INAA values for most of the geochemical reference samples analysed in the present study.     

Determination of Halogens (F, Cl, Br, I), Sulfur and Water in Seventeen Geological Reference Materials

Fluorine, chlorine, bromine, iodine and sulfur were determined in seventeen geological reference materials after extraction by pyrohydrolysis. Fluorine, Cl and S (as sulfate ions) were determined in the extraction solution by ion chromatography with detection limits of around 0.2 mg l⁻¹. Bromine and I were measured by ICP-MS with detection limits of 1 μg l⁻¹ for Br and 0.1 μg l⁻¹ for I. For rock samples, using normal extraction conditions (500 mg of sample and 100 ml of final solution) detection limits were 40 mg kg⁻¹ for F and Cl, 15 mg kg⁻¹ for S, 0.2 mg kg⁻¹ for Br and 0.02 mg kg⁻¹ for I. These detection limits may be improved by increasing the amount of sample and hence the concentration of the final solution. Water was also determined using an extraction technique based on H₂O degassing, reduction on zinc at 1000 °C and H₂ manometry. Our results for fluorine, chlorine, sulfur and water are in good agreement with literature data. Very few reference materials have recommended values for bromine and especially for iodine. Among the analysed samples, three are new reference materials: BHVO-2, BCR-2 and AGV-2.     

1992 compilation of analytical data for rare-earth elements, scandium, yttrium, zirconium and hafnium in twenty-six GSJ reference samples

Abstract: Analytical data for fourteen rare-earth elements, scandium, yttrium, zirconium and hafnium, received by May 1992, have been compiled on twenty-six GSJ (Geological Survey of Japan) reference samples. Seventeen of them are 'Igneous rock series' and nine are "Sedimentary rock series". The reported data including personal communication were evaluated under the consideration on analytical methods and geochemical evidences. No significant difference has been observed between the values obtained by the different analytical methods. Based on the selected available data, 1992 compilation values were tabulated.     

Geometric Means as Probable Values For Compiled Data on Geochemical Reference Samples

Trace element data compiled on, geoshemical reference samples present invariably skewed distributions. It is proposed to treat such data as lognormally distributed and to compute geometric means (X_gm) as probable values. As examples, the X_gm values derived for some trace elements in some rock reference samples are compared with the "recommended" values and with the "gamma" values of Christie.     

DETERMINATION OF BROMINE AND IODINE IN FOUR MARINE SEDIMENT REFERENCE SAMPLES BY ENERGY-DISPERSIVE X-RAY FLUORESCENCE SPECTROMETRY

The concentrations of bromine and iodine in the USGS marine mud MAG-1, the NRCC marine sediments BCSS-1 and MESS-1, and the NBS estuarine sediment SRM 1646 have been determined by energy-dispersive x-ray fluorescence spectrometry. Matrix and intermediate thickness effects were overcome by standard additions to constant weights of each sample. 3-sigma detection limits are 6 ppm Br and 24 ppm I. There is a need for many more analysts to report their results before "usable values'can be established for these elements in marine sediment reference malterials.     

Standard Reference Material of Fluorite FM

Standard reference material of fluorite FM, consisting chiefly of fluorite, quartz and baryte, was prepared by the Institute of Mineral Raw Materials in Kutná Hora (Czechoslovakia). The homogeneity of the pulverised SRM was checked by X-ray fluorescence spectrometry from counts corresponding to the amounts of iron, copper, barium, strontium and titanium. The SRM was considered homogeneous if the "between bottles" variance was not significantly greater than the "within bottles" variance and further, if the error caused by heterogeneity of the SRM was less than one third of the error of an analytical determination carried out in a routine manner. Analytical results from 26 laboratories were processed following the recommended procedure of CMEA-countries which includes: Testing the normality of results, eliminating out-lying results and computing the arithmetic means, estimates of standard deviations and the confidence intervals of the means. Attested values for 17 components and non-attested values for 30 components and/or elements are reported.     

大同盆地地下水中碳硫同位素组成特征及其对碘迁移富集的指示

为深入探究地下水系统中影响碘迁移转化的主控水文生物地球化学过程,对大同盆地典型高碘地下水区完成样品采集,分析地下水样品基础理化性质及碳硫同位素组成特征.结果表明,大同盆地地下水碘含量变化范围为14.40~1 030.00 μg/L,高碘地下水（I>100 μg/L）主要分布在盆地中心排泄区.地下水中溶解性无机碳的δ13C_DIC值变化范围为-12.11‰~-9.79‰,硫酸盐δ34S_SO4值介于4.04‰~16.63‰.δ13C_DIC和DOC之间存在较明显的正相关关系,表明有机质的微生物降解过程是区域地下水无机碳的重要来源之一.同时,δ13C_DIC与δ34S_SO4一定的负相关关系表明硫酸盐是有机质微生物降解过程中潜在电子受体之一,且地下水水环境以偏还原环境为主.高碘地下水表现出低δ13C_DIC、高δ34S_SO4的同位素特征,表明有机质的微生物降解过程是控制地下水中碘迁移释放的主要过程之一,与该过程相伴而生的碘形态转化进一步促使碘以碘离子的形式在偏还原的地下水环境中发生富集.      

DETERMINATION OF FLUORINE, CHLORINE, BROMINE AND IODINE IN SEVEN GEOCHEMICAL REFERENCE SAMPLES

The concentrations of fluorine, chlorine, bromine and iodine of seven geochemical reference samples have been determined. Analytical techniques were neutron activation analysis for chlorine, bromine and iodine and ion-selective potentiometry for fluorine. After irradiation of the samples, these halogens were separated from the matrix elements by pyrohydrolysis in presence of vanadium (V) oxide. This extraction allows to measure the four halogens in the same sample.