A review is presented regarding the problems in the assignment of values for individual components of reference samples of silicate rooks. Possible causes are examined for the disparity of data obtained from contributing laboratories and for the fact that there has been little improvement over the years. Differences between collaborative programmes on rocks and those on ores are emphasized, particularly regarding the imbalance resulting from the inability to maintain adequate control over operations involving so many varied components. A plea is made for more careful interpretation of published values, for more meaningful description of analytical methods used and for more uniform practices in programmes originating in various countries. An argument is presented in favor of tempering statistical treatment with subjective considerations, and several tentative tests are proposed for verifying the validity of derived values.
More than 40 trace elements in 11 Chinese geological reference materials (stream sediments) GSD-1 to GSD-7 and GSD-9 to GSD-12 were determined by inductively coupled plasma-mass spectrometry (ICP-MS). Open acid digestions were used to prepare samples for the determination of most elements. However, for the measurement of Y, Zr and Hf, it was found necessary to use an alkali fusion in order to make fully quantitative measurements. The results obtained in this work are generally in good agreement with the recommended values from the sub-ppm level to > several hundred ppm and illustrate the versatility of the technique, particularly for some less well characterised elements.
Refinements have been made to achieve over 99% yield in the conversion of CO to CO2 in order to improve the reproducibility and accuracy of δ18O measurements in sulfates. BaSO4 (10-15 mg) was mixed with an identical amount of spectrographic-grade graphite and loaded into a Pt boat. The mixture was gradually heated to 1100 °C to reduce sulfate to CO and CO2; the former gas was simultaneously converted to CO2 by a glow discharge between Pt electrodes immersed in a magnetic field (produced by a pair of external neodymium magnets). A small memory effect was noticed during the analysis (less than 0.3% per 10% difference in δ18O between two subsequently analysed samples). The memory effect, however, was suppressed by repetitive preparation of the same specimen. CO2 produced in this way from sulfate reference samples was analysed on a dual inlet and triple collector mass spectrometer along with CO2 equilibrated with VSMOW, GISP and SLAP water reference samples. To avoid large departures of measured isotope ratios from 18O/ 16O of the working calibrator we used CO2 gas prepared from ocean water sulfate for this purpose. The calibrated δ18O values (in %0) obtained in this way for NBS-127, IAEA SO-5 and IAEA SO-6 reference materials were 8.73 ± 0.05, 12.20 ± 0.07 and -10.43 ± 0.12, respectively.
Third in the series of collaborative studies launched by the International Working Group “Analytical Standards of Minerals, Ores and Rocks” (IWG), the study on Ailsa Craig Granite AC-E has attracted the participation of 128 laboratories from 29 countries. Tables of compiled data, 3212 results in all, are presented with working values, recommended or proposed, for seventy major, minor and trace elements. The success of this study which lasted for only one year from the distribution of sample to the release of the present report is to be attributed entirely to the record participation of the IWG-Member laboratories.
The calcium isotopic composition of NIST SRM 915b and 1486 provided by the National Institute of Standards and Technology was analysed. The δ44/40Ca values of the two reference materials relative to NIST SRM 915a were: NIST SRM 915b =+0.72 ± 0.04‰ and NIST SRM 1486 =−1.01 ± 0.02‰. NIST SRM 1486 did not require any chemical separation prior to measurement.
La composition isotopique du calcium de NIST SRM 915b et 1486, fournis par l'Institut National des Standards et de la Technologie (NIST), a été analysée. Les valeurs du δ44/40Ca obtenues sur ces deux matériaux de référence, relativement au NIST SRM 915a sont: NIST SRM 915b =+0.72 ± 0.04‰ et NIST SRM 1486 =−1.01 ± 0.02‰. Le NIST SRM 1486 n'a nécessité aucune séparation chimique avant analyse.
Preliminary results are given from an excimer 157 nm laser ablation multiple-collector inductively coupled plasma-mass spectrometer (LA-MC-ICP-MS), used for the isotopic measurements of solid materials. Elements of geological interest with different volatilities such as Pb and U (e.g. zircon geochronology) and Cu and Zn (as examples of geochemical/biochemical tracers) were analysed. The range of ablation rates of 20-150 nm s-1 enabled us to ablate the sample down to a depth of 45 μm for a 50 μm diameter pit. The Cu and Zn isotopic measurements gave values that were very stable with, on average, a 0.01 % standard error, comparable with that achieved in liquid mode measurements.Des résultats préliminaires d'analyses isotopiques sur des matériaux solides ont été obtenus en utilisant un système d'ablation laser de type Excimer 157 nm coupléà un spectromètre de masse avec source à plasma induit (LA-MC-ICP-MS). Des éléments d'intérêt géologique ayant des volatilités très différentes, tels que Pb, U (applications en géochronologie sur zircon) Cu et Zn (représentatifs de traceurs bio-géochimiques) ont été analysés. La vitesse d'ablation, de l'ordre de 20 à 150 nm s-1 nous a permis de travailler sur des cratères d'une profondeur de 45 μm et 50 μm de diamètre. Les mesures de rapports isotopiques de Cu et Zn donnent des valeurs très stables, avec une erreur standard moyenne de 0.01%, ce qui est comparable avec ce qui est obtenu en analysant des solutions.
The concentration of molybdenum in 16 U.S. Geological Survey (USGS) standard rocks was determined by a colorimetric procedure using zinc dithiol reagent. The molybdenum content in the rocks was found to range from 0.04 to 37 ppm. The precision of the method is generally better than 10% relative deviation when the molybdenum content is >0.3 ppm. A comparison with values stated in the literature shows that the method is accurate for the range of concentrations determined and the rock types analyzed.
Seven soil geochemical certified reference materials (CRMs) GSS 10-16 recently prepared by the Institute of Geophysical and Geochemical Exploration (IGGE), are mainly used for sample analysis in geochemical surveys of the overburden region in China. Fifteen Chinese institutes and central laboratories, which operated at a high level of analytical performance analysed these samples. More than ten reliable analytical methods based on different principles of measurement were adopted, of which ICP-MS, ICP-AES and NAA were taken as the primary analytical methods. In total, 23715 determinations were carried out, 5660 average data sets were obtained, seventy two elements and components were determined and certified values of sixty nine elements and components were assigned. Rhenium concentrations were measured by isotope dilution ICP-MS in GSS-10, GSS-13, GSS-15 and GSS-16. Certified values of elements in GSS 10-16 have good precision and for 90% of these values relative uncertainties are less than 10%.
Instrumental neutron activation analysis has been applied to the analysis of recently issued NBS reference materials SRM 1633a Fly Ash and SRM 1632a Bituminous Coal. Only the nuclides with half-lives of less than 48 hours have been used. The results for the determination of 18 elements (Fly Ash) and 19 elements (Coal) are compared with the values given by NBS and with recent results obtained by other investigators.
During 1975–1977, the USGS reference rocks GSP-1, BCR-1 and from 1977 onwards AGV-1 have been systematically analysed in routine INAA as test samples. The results are given for up to 26 elements per sample and the reliability of our setup is demonstrated. For further 17 geochemical reference samples, new results are presented and compared with available data.
A short preamble is devoted to an explanation of how the data were presented in the long appendices. There are four tables: 1) gives details of abbreviations used; 2) lists the 170 samples by sample number; 3) lists them in alphabetical order and 4) lists major and minor elements in each sample in order of increasing SiO2 content. Appendix 1 gives working values for major, minor and trace elements in each of the 170 reference samples. Appendix 2 gives working values element by element in increasing order of concentration. Appendix 3 identifies each sample and its source. Appendix 4 is a list of references for Appendices 1 and 3. -B.Ls.
In this study, the Cd isotopic composition of various geological reference materials and anthropogenic samples was investigated. The measurements were made by multicollector ICP-MS and instrumental mass fractionation was controlled using a "sample-standard bracketing" technique. Cadmium isotopic data are reported relative to an internal Cd solution (Cd Spex) and expressed as the 114Cd/ 110Cd delta value. Two other Cd solutions (Prolabo and JMC) were analysed and yielded the same 0‰ delta value. A fractionated Cd metal sample (Münster Cd) was used as a secondary reference material for Cd isotopic measurements and we obtained a 114Cd/ 110Cd delta value of 4.48‰ relative to Cd Spex solution. As opposed to multi-stage Cd purification previously published in the literature, a new one step anionic exchange purification using dilute HCl for the analysis of Cd isotopes in geological samples was developed. This method enabled a high recovery (> 95%) and effective separation of the sample matrix to be achieved. The long-term external reproducibility was evaluated at 0.12‰ (2 standard deviations) for the 114Cd/ 110Cd ratio, based on reference solutions and replicated measurements of samples over one year. The variation of Cd isotopic composition of natural terrestrial samples is restricted to a small range of 0.4‰, which is similar to previously reported results. In contrast, large variations of Cd isotopic composition were found for anthropogenic samples with values as low as -0.64‰ for a dust sample issued from a lead smelter and values as high as +0.50‰ for NIST SRM 2711 (metal-rich soil). These variations are 10 times larger than the reproducibility and suggest that Cd isotopes can be useful as tracers of anthropogenic sources of Cd in the environment.
A selective and sensitive method for the extraction and spectrophotometric determination of gold with N,N′-6,7,9,10,17,18,20,21-octahydrodibenzo[b,k][1,4,7,10,13,16] hexaoxacyclo-octadecine-2,13–diylbis(2-chloroacetamide) (ODBOCA) is described. The ODBOCA–Au(III) complex was extracted from a slightly acidic aqueous solution (pH 5) into a chloroform layer and then the absorbance of the extract was measured using a UV–Vis spectrophotometer with 1.0 cm quartz cells at 540 nm. An enrichment factor of 200 was achieved. In the chloroform medium at 540 nm, the molar absorptivity and Sandell’s sensitivity were 4.12 × 10³ l mol⁻¹ cm⁻¹ and 0.048 μg cm⁻², respectively. Beer’s law was obeyed in the range of 0.5–15 μg ml⁻¹ in the measured solution. The relative standard deviation for ten replicate samples at the 1.0 μg ml⁻¹ level was 3.0%. The limit of detection, based on 3s, was 0.5 μg l⁻¹ in the original sample. The effects of pH, ligand concentration and shaking time were studied. The ratio of the metal ion to ligand molecules in the complex was found to be 1:2 according to the Job Method. The effects of interference by a number of metal ions were investigated. The method was verified with certified reference materials and spiked tests, and quantitative recovery values were obtained. The method was fast, accurate, selective and precise, and was applied to the determination of gold in water and ore with good results.
International carbon and oxygen isotope calibration material NBS 19 and reference materials NBS 18, International Atomic Energy Agency (IAEA)-CO-1 and IAEA-CO-8 are prepared from naturally occurring rock specimens of marble and carbonatite. Mineralogical and chemical analysis showed that only NBS 19 and IAEA-CO-1 represent essentially pure samples of calcite containing < and minimal (< 1%) quantities of quartz. In contrast, both NBS 18 and IAEA-CO-8, although primarily composed of calcite, are contaminated by a range of additional phases. NBS 18 was estimated to contain 1% Fe-dolomite and trace (< 1%) quantities of apatite and quartz. IAEA-CO-8 was estimated to contain at least 4% non-carbonate material (including apatite, barite, biotite and magnetite). NBS 18 and IAEA-CO-8 are both derived from samples of carbonatite and the calcite component of each material is characterised by appreciable substitution of Mg + Mn + Sr ± Fe ± Ba (Σ ≈ 14000–15000 μg g⁻¹) for Ca. The observations reported in this study complement data in the literature detailing significant grain-scale isotopic heterogeneity in NBS 18 and IAEA-CO-8. Both data sets highlight the need for careful characterisation of calibration materials prior to distribution.
In the past, there has been little interest in the trace element characteristics of quartz, and in consequence little activity in the trace element characteristics of reference materials with high silicon content. The main purpose of this paper is to contribute to the characterisation of two international certified reference materials, BCS 313/1 from the Bureau of Analysed Samples, (BAS), UK and SRM 1830 from the National Institute of Standards and Technology (NIST), USA. BCS 313/1 was analysed by laser ablation inductively coupled plasma-mass spectrometry (LA-ICP-MS), solution ICP-MS and instrumental neutron activation analysis (INAA). NIST SIRM 1830 was analysed by LA-ICP-MS and INAA. Analytical results are reported for more than forty elements, most of them for the first time. For most elements, the results obtained by the different methods agree within 15% relative. The recent, heightened interest in quartz and in particular the precise determination of trace element contents in natural quartz samples requires the use of well-characterised reference materials such as BCS 313/1 and SRM 1830, to which this study is designed to contribute.
We report on the major and trace element composition and homogeneity of NIST (National Institute of Standards and Technology) glass standard reference materials 611, 612, 614, and 1834 for use as microanalytical trace element standards in laser ablation-inductively coupled plasma-mass spectrometry. The four analyzed NIST glasses were not designed as microanalytical standards, but their availability and careful preparation made them obvious candidates. Our data indicate that NIST 1834 is inhomogeneous on a scale of 100 mg with respect to several trace elements. Within analytical uncertainty, NIST 611, 612, and 614 are apparently homogeneous.
Two types of gold deposit with both good homogeneity and a high-grade of gold were selected to prepare four gold ore reference materials (GAu-19,GAu-20,GAu-21 and GAu-22) by the Institute of Geophysical and Geochemical Exploration (IGGE),China.Seven laboratories participated in the certification programme. Volumetric methods for GAu19-21 and atomic absorption spectrometry for GAu-22 were used for the homogeneity testing,the coefficient of variation being found to be less than 3%.After sample digestion and preconcentration,the samples were analysed by flame atomic absorption spectrometry (AAS),colorimetry,neutron activation analysis (NAA)and volumetric analysis. The certified values for the gold concentration in GAu19-22 are 18.3 μg g -1, 32.3 μg g -1, 53.0 μg g -1 and 5.72 μg g -1,respectively.Deux types de gisements d'or, présentant à la foisune bonne homogénéité et une teneur élevée en or, ont été sélectionnés par l'Institut d 'Exploration Géophysique et Géochimique de Chine (IGGE)afin de préparer quatre matériaux de référence pour l'or (GAu-19,GAu-20,GAu-21 et Gau-22). Sept laboratoires ont participé au programme de certification.Des méthodes volumétriques (GAu-19-21)et de spectrométrie par absorption atomique (GAu 22)ont été utilisées pour tester l'homogénéité de ces échantillons;les coefficients de variation se sont révélés inférieurs à 3%.Après la mise en solution et la préconcentration des échantillons,ceux-ci ont eté analysés par spectrométrie d 'absorption atomique (AAS), colorimétrie,activation neutronique (NAA)et analyse volumétrique.Les valeurs certifiées pour la concentration en or de GAu19-22 sont respectivement de 18.3 μg.g -1,32.3 μg g -1, 53.0 μg g -1 et 5.72 μg g -1.
The GENESIS space mission recovered ions emitted by the Sun during a 27 month period. In order to extract, purify and determine the very low quantities of solar nitrogen implanted in the GENESIS targets, a new installation was developed and constructed at the CRPG (Nancy, France). It permitted the simultaneous determination of nitrogen and noble gases extracted from the target by laser ablation. The extraction procedure used a 193 nm excimer laser that allowed for surface contamination in the outer 5 nm to be removed, followed by a step that removed 50 nm of the target material, extracting the solar nitrogen and noble gases implanted in the target. Following purification using Ti and Zr getters for noble gases and a Cu-CuO oxidation cycle for N(2), the extracted gases were analysed by static mode (pumps closed) mass spectrometry using electron multiplier and Faraday cup detectors. The nitrogen blanks from the purification section and the static line (30 minutes) were only 0.46 picomole and 0.47 picomole, respectively.
New glass reference materials GSA-1G, GSC-1G, GSD-1G and GSE-1G have been characterised using a prototype solid state laser ablation system capable of producing wavelengths of 193 rim, 213 nm and 266 nm. This system allowed comparison of the effects of different laser wavelengths under nearly identical ablation and ICP operating conditions. The wavelengths 213 nm and 266 nm were also used at higher energy densities to evaluate the influence of energy density on quantitative analysis. in addition, the glass reference materials were analysed using commercially available 266 nm Nd:YAG and 193 nm ArF excimer lasers. Laser ablation analysis was carried out using both single spot and scanning mode ablation. Using laser ablation ICP-MS, concentrations of fifty-eight elements were determined with external calibration to the NIST SRM 610 glass reference material. instead of applying the more common internal standardisation procedure, the total concentration of all element oxide concentrations was normalised to 100%. Major element concentrations were compared with those determined by electron microprobe. in addition to NIST SRM 610 for external calibration, USGS BCR-2G was used as a more closely matrix-matched reference material in order to compare the effect of matrix-matched and non matrix-matched calibration on quantitative analysis. The results show that the various laser wavelengths and energy densities applied produced similar results, with the exception of scanning mode ablation at 266 nm without matrix-matched calibration where deviations up to 60% from the average were found. However, results acquired using a scanning mode with a matrix-matched calibration agreed with results obtained by spot analysis. The increased abundance of large particles produced when using a scanning ablation mode with NIST SRM 610, is responsible for elemental fractionation effects caused by incomplete vaporisation of large particles in the ICP.
Publication patterns of CCRMP, NIST, and USGS reference materials are traced over the past 40 years by literature source, analytical method employed, and constituents measured. This is the first update to our 1987 paper which covered the period 1951 - 1985.
The five CRPG geochemical reference samples (BR, GA, GH, Mica-Fe and Mica-Mg) have been distributed as reference samples for more than twenty years. All data on trace elements in these samples available to the authors since their first reports have been compiled and evaluated. It has been possible to assign working values for more than forty elements in BR, GA, GH and Mica-Fe and for twenty-three elements in Mica-Mg. The samples are expected to last for another twenty years.
All data reported by 200 analysts (106 laboratories) are presented for the four ANRT samples: Diorite DR-N, Serpentine UB-N, Bauxite BX-N and Disthène DT-N. Recommended values are given for the major and minor elements. As far as the as trace elements are concerned, DR-N has been characterized for 35 elements whereas the other three samples have been for only 20 elements. Wherever possible, brief comments have been inserted so as to explain our way of assigning recommended or proposed values.After more than a decade of existence the total number of data reported for all the four samples reach only 3200 units which are not sufficient enough for a valid evaluation of compiled data. It is also pointed out that these samples are most likely to be available even during the next century as they have been prepared in large quantities of the order of one ton. A plea is therefore made for contribution of more data particularly for trace elements and for major elements which are present as trace elements in UB-N, BX-N and DT-N.
Since 1967–68, two mica reference samples, Biotite Mica-Fe and Phlogopite Mica-Mg, were made available to several geochemical laboratories. The analytical data reported during the past ten years by 142 geoanalysts belonging to 74 international laboratories are presented and assessed for deriving preferred values. Reaomrmended or proposed values are assigned for major, minor and several trace elements. The biotite Mica-Fe is better characterized for its chemical composition than the Phlogopite Mica-Mg. Both the samples are also proposed as geochronological standards. Because very few mica reference samples have been processed in large quantities, the international geochemiaal community is invited to contribute further useful data.
Granite GS-N and Potash Feldspar FK-N are two ANRT reference samples prepared in 1973 in 960 and 567 kg, respectively. All data reported since 1973 are compiled in this report. GS-N and FK-N are now well characterized for major and minor elements. As for trace elements, working values have been assigned for 36 elements in GS-N and for 30 elements in FK-N. We need much more data on trace elements for characterizing them better. As GS-N and FK-N are still available in large quantities and are certain to remain so for two or three decades to come, a plea is made for contribution of more data on trace elements.
A brief outline is given of the approach used in the Canadian Certified Reference Materials Project (CCRMP) to prepare and certify reference ores and related materials. Recommended values and 95 % confidence intervale are tabulated for selected constituents in 18 reference materials. Future plans of the CCRMP are outlined also.
Les résultats d'un grand nombre de dosages de potassium et d'argon effectués sur des échan tillons standards sont présentés; les âges K-Ar correspondant sont également calculés. Il s'agit d'une part de standards géochronologiques: la muscovite Berne 4M, la biotite LP6 et la phonolite MZ, d'autre part de standards géochimiques diffusés par le CRPG: la biotite Mica-Fe, la phlogopite Mica-Mg et le basalte BE-N.
Three rock reference samples, Anorthosite AN-G, Basalt BE-N and Granite MA-N were analysed for their chemical composition by 122 laboratories belonging to the International Working Group “Analytical Standards of Minerals, Ores and Rocks” (IWG). 243 analysts took part in this first collaborative study which lasted only nine months, from June 1979 to March 1980. Despite this very short period, it has been possible to harvest over 6000 units of analytical data on major, minor and 53 trace elements. This excellent performance of the IWG members has rendered possible the chemical characterization of the three samples for not only the usual major and minor elements but also for 30 trace elements. This first study by the IWG Members demonstrates well their immense analytical potential and is exemplary in many respects.
Concentration data for as many as 64 constituents in the six United States Geological Survey's (USGS) Geochemical Exploration Reference Samples (GXR) have been collected from journal articles and technical reports published since these reference materials were issued in 1971. These data are summarized into mean +/- one standard deviation values and compared with our previously calculated concentrations based upon USGS round-robin data published in 1978. All new literature data located are presented in the appendices.
Elemental composition data on eight older (AGV-1, BCR-1, DTS-1, G-1, G-2, GSP-1, PCC-1 and W-1) and three newer (BIR-1, DNC-1 and W-2) USGS rock standards have been collected from institutional reports and journal articles from 1972-1981. This comprehensive compilation gives consensus values for the first eight standards as well as means and medians for each element both overall and by method. There are lists of the 49 journals surveyed and the source references of the individual data. These compiled data for the 11 standards form the bulk of the paper. -B.Ls.
Concentration data for as many as 72 constituents in the four Canadian Certified Reference Materials Project (CCRMP) soil samples have been collected from journal articles and technical reports published since these soil standards were issued in 1978. These data are summarized into mean +/- one standard deviation values and compared with available certification data from CCRMP. All literature data located or calculated are presented in the appendices.
For the two IWG reference samples, Albite AL-I and Iron Formation Sample IF-G, new data on trace elements and those published in the 1984 compilation report are presented along with a brief description of their preparation in large quantities, 169 kg for AL-I and 760 kg for IF-G. Recommended working values with confidence limits have been assigned for over fifty major, minor and trace elements. A distinguishing feature of both the samples is their low abundances of trace elements.
During the five-year period (April 1981 - March 1986), a series of fifteen rock reference samples, “Igneous rock series”, has been prepared by the Geological Survey of Japan (GSJ). Based on the data available (published and communicated), consensus values for major, minor and trace elements have been derived; these values are presented for this second series of samples as well as for the first series of two samples, Granodiorite JG-1 and Basalt JB-1.
Improved determinations of uranium and thorium by fission track and moderating neutron techniques are presented for the rock reference samples of the Geological Survey of Japan (GSJ) “Igneous rock series 1986”. The non-homogenous distribution of uranium and thorium has been detected in the samples JF-1, JG-2 and JG-1a caused by the presence of highly radioactive accessory minerals.
On présente ici une amélioration des déterminations des concentrations en uranium et thorium due à l'utilisation couplée des traces de fission et de l'activation neutronique modérée. L'application en est faite sur des échantillons de roche de référence du service Géologique du Japon (GSJ) appartenant à la série “roches ignées 1986”. Une distribution non homogène de l'uranium et du thorium a été détectée dans les échantillons JF-1, JG-2 et JG-1a, liée à la présence de minéraux accessoires hautement radioactifs.
Elemental concentration data on up to 84 individual constituents in BHVO-1, MAG-1, QLO-1, RGM-1, SCo-1, SDC-1, SGR-1 and STM-1 have been collected from 311 journal articles and technical reports. These data are summarized in consensus (mean) values with uncertainties expressed as one standard deviation. Mean values are also calculated as a function of analytical procedure and all raw data are given in the tables.Ce rapport rassemble des données analytiques parues dans 311 articles scientifiques ou rapports techniques sur 84 éléments dans huit échantillons du Service Géologique des Etats-Unis: BHVO-1, MAG-1, QLO-1, RGM-1, SCo-1, SDC-1, SGR-1 et STM-1. Quand cela a été possible, les valeurs de consensus (moyenne) sont présentées pour chaque élément avec l'incertitude exprimée en un écart-type. Des valeurs moyennes en fonction des procédures analytiques sont également présentées.
Concentration data on up to 91 individual constituents in USGS DTS-1, G-1, PCC-1, and W-1 have been collected from 1647 journal articles and technical reports. These data are summarized in consensus (mean) values with uncertainties expressed as one standard deviation. Mean values are also calculated as a function of analytical procedure and all raw data are given in the tables. Recommended values are proposed based upon data criteria used by NIST (National Institute of Standards and Technology, formerly the National Bureau of Standrds or NBS).
Concentration data on 74 individual constituents in CCRMP (Canadian Certified Reference Materials Project) soils SO-1, SO-2, SO-3, and SO-4 have been collected from 83 journal articles and technical reports. These data are summarized in consensus (mean) values with uncertainties expressed as one standard deviation. Mean values are also calculated as a function of analytical procedure and all raw data are given in the tables. Recommended values are proposed based upon data criteria used by NIST (National Institute of Standards and Technology, formerly the National Bureau of Standards or NBS).
Concentration data on up to 82 individual constituents in USGS Basalt BCR-1 have been collected from 1395 journal articles and technical reports. These data are summarized in consensus (mean) values with uncertainties expressed as ± one standard deviation. Mean values are also calculated as a function of analytical procedure and all raw data are given in the tables. Recommended values are proposed based upon data criteria used by NIST (National Institute of Standards and Technology, formerly the National Bureau of Standards or NBS).
Concentration data on 73 individual constituents in United States Geological Survey (USGS) Geochemical Exploration Reference Materials GXR-1 to GXR-6 have been collected from 131 journal articles and technical reports. These data are summarized as consensus (mean) values with uncertainties expressed as one standard deviation. Mean values are also calculated as a function of analytical procedure and all raw data are given in the tables. Recommended values are proposed based upon data criteria used by NIST (National Institute of Standards and Technology, formerly the National Bureau of Standards or NBS).
Concentration data on up to 90 individual constituents in USGS AGV-1, GSP-1, and G-2 have been collected from 1270 journal articles and technical reports. These data are summarized in consensus (mean) values with uncertainties expressed as +/- one standard deviation. Mean values are also calculated as a function of analytical procedure and all raw data are given in the tables. Recommended values are proposed based upon data criteria used by NIST (National Institute of Standards and Technology, formerly the National Bureau of Standards or NBS).
Concentration data on 80 individual constituents in Canadian Certified Reference Materials Project rock reference materials SY-2, SY-3, and MRG-I have been collected from 382 journal articles and technical reports. These data are summarized as consensus (mean) values with uncertainties expressed as one standard deviation. Mean values are also calculated as a function of analytical procedure and all raw data are given in the tables. Recommended values are proposed based upon data criteria used by NIST (National Institute of Standards and Technology, formerly the National Bureau of Standards or NBS).
The six ANRT rock reference samples (DR-N, UB-N, BX-N, DT-N, GS-N, FK-N) have been distributed as reference samples for nearly twenty years. All available data on trace elements in these samples are presented and evaluated. It has been possible to assign working values for nearly 40 trace elements. These samples prepared in 600 to 1300 kg quantities are expected to last for some decades to come.
In this special issue, working values are reported for 272 international geostandards along with sample description. For many geostandards, the number of compiled data were not adequate enough for assigning working values. Users of geostandards are solicited to contribute more and more data particularly on trace elements. Think Geostan is a slogan that we wish to launch to set this problem in the limelight.