Determination of Silver in Seventy-Three Geochemical Reference Samples by Atomic Absorption Spectrometry

The silver content of seventy-three geochemical reference samples has been determined by atomic absorption spectrometry using an air-acetylene flame or a graphite furnace atomizer, after extraction of silver as iodide with methyl isobutyl ketone (MIBK). A comparison with published data shows clearly the need for much more data on most reference samples.     

Silver, Cadmium and Lead Contents of Some Rock Reference Samples

A series of rock reference samples have been analyzed for Ag, Cd and Pb. All elements were determined from a single digest using a method involving solvent extraction and flameless atomic absorption spectrophotometry.     

硅酸盐岩石中硅的流动注射分析

本文研究了用流动注射-光度法测定硅酸盐岩石中硅的实验条件,建立了一个可靠的测定高含量硅的方法,精密度和准确度良好。对标准参考岩石样品分析结果与推荐值吻合。     

Determination of Chlorine in Nine Rock Reference Materials by Isotope Dilution Mass Spectrometry

A procedure for the determination of chlorine by the isotope dilution technique (ID) using negative thermal ionisation mass spectrometry (N-TIMS) is described. Silicate samples of about 10 mg were spiked and decomposed with hydrofluoric acid, and chlorine was isolated by precipitation of silver chloride after neutralisation with Ca(OH)₂. The ammonical solution of AgCl was then subjected to N-TIMS. Replicate analyses of rock reference materials, typically of JB-1 and JR-1, demonstrated the high quality of the analyses (precision for Cl was ± 1-2%). We present here the most precise data sets of chlorine concentrations in nine igneous rock reference materials, three basalts (JB-1, JB-2, JB-3), two andesites (JA-3, AGV-1), two rhyolites (JR-1, JR-2) and two granodiorites (JG-3, GSP-1). The chlorine concentrations found ranged from 152 μg g-1 in AGV-1 to 1008 μg g^-1 in JR-1. Our results presented here are partly (but not completely) in agreement with recommended values, where they are available. The N-TIMS ID technique can thus be used as a means of determining low chlorine contents in silicate materials to high precision.     

Determination of Gold, Silver and Platinum-Group Elements in Geochemical Reference Materials by Direct Atomic Emission Spectral Analysis Using a Multichannel Analyser Recording Device

A procedure for the analysis of geochemical samples has been developed based on direct atomic-emission spectrometry for the determination of silver, gold and the platinum-group elements. Instrumentation comprised a DC arc emission two-jet plasmatron coupled to a diffraction spectrograph and multichannel analyser for recording emission spectra. Spectrum analysis used a comprehensive library of spectral lines for practically all elements excited using this emission source. The software programme for the automatic registration of spectra and subsequent data processing are described and results presented for a number of geochemical reference materials.     

Determination of Rare Earth Elements in Sixteen Silicate Reference Samples by Secondary Ion Mass Spectrometry Using Conventional Energy Filtering Technique*

Rare earth elements were determined by secondary ion mass spectrometry for 13 silicate rock samples, ranging from ultramafic-mafic to acidic compositions, 2 feldspar and 1 biotite separates. As a whole, the investigated samples are characterized by matrices and rare earth elements spectra covering most geological applications. The present data are compared with reference values. The advantage of using secondary ion mass spectrometry as a fundamental tool for trace element detection in bulk samples in the few ppm-ppb region is demonstrated.     

Available Clay and Feldspar Reference Samples As Standards for Archaeological Pottery Studies

The available clay and feldspar reference samples, rather than the frequently used rock reference samples, are suggested as standards for archaeological pottery studies because their trace-element contents are more like those of the artefacts. Such samples may provide a basis for correlating archaeological studies throughout the world. The assumption that bottles of such reference samples should have homogeneous trace-element contents because of the nature of the materials has been confirmed by the analysis of variance of trace -element data by instrumental neutron activation analysis.     

1986 Values for Fifteen GSJ Rock Reference Samples, "Igneous Rock Series"

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.     

Silver Content of Some USGS Standard Rocks

The state of the art for silver determination in silicate rocks is discussed on the basis of available data on geostandards. A neutron activation procedure for silver in rocks is briefly described, and data on seven new USGS standard rocks are presented and discussed.     

Determination of Selenium in Geochemical Reference Samples Using Flameless Atomic Absorption Spectrometry

Sixteen international and six inter-laboratory geochemical reference samples have been analysed for their selenium content. No previous Sedata are available for thirteen of them. Selenium has been separated from silicate matrix by volatilization and was determined with flameless atomic absorption spectrometry. An outline of the procedure is given. The limit of detection is 10 ng Se per 1 g of sample. Time required for one full analysis is 1.2 to 2.5 hours depending on amount of sample to be volatilized.     

Uranium and Thorium Content of Reference Samples from the Geological Survey of Japan "Igneous Rock Series 1986"

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.     

Mass Spectrometric Isotope Dilution Determination Of Palladium in Geochemical Reference Samples

Fifteen geochemical reference samples have been analysed for palladium using the stable isotope dilution technique. These include seven USGS, five CRPG and three CCRMP samples. Our results ape in reasonable agreement with the presently accepted values for the USGS samples, but are significantly lower than the present CCRMP values. Our data for the CRPG samples are the first to be published. This is the first reported study of the determination of palladium in silicate samples using the isctope dilution technique.     

Determination of Thorium-230 in CCRMP Reference Samples by Alpha Spectroscopy

Thorium-230 concentrations have been determined in 11 CCRMP (Canadian Certified Reference Materials Project) reference rock and ore samples using alpha spectroscopy following a chemical separation of the thorium. Literature data are available for only one of these 11 reference samples.     

Determination of Zirconium in Carbonate Rock Reference Materials with Xylenol Orange Spectrophotometric Method

The zirconium content of six carbonate rock reference samples has been determined by a spectrophotometric method using xylenol orange after sample decomposition by acid digestion or alkali fusion. The interference of calcium was eliminated by adding the same concentration of calcium to the blank solution.     

Reference samples for use in analytical geochemistry: their availability, preparation, and appropriate use

A large number of certified and other reference samples are available for use in analytical geochemistry. Certified materials are preferred, but of much more limited availability than other reference samples for most geochemical applications. The availability of rock, sediment, soil, water, and plant reference samples is outlined; ore and mineral separate reference samples are not included in the discussion. The preparation of these materials, including the establishment of certified or recommended concentrations, is then reviewed. It is shown that comparable quality can be achieved for both certified and recommended concentrations, though it has not always been achieved in the past. Finally, the most appropriate ways to use reference samples in quality control and instrumental calibration are discussed.     

Mass spectrometric isotope dilution analyses of cadmium in standard rocks

Cadmium has been determined in a range of silicate rock standards using the stable isotope dilution technique incorporating solid source mass spectrometry. Our recommended values are, in general, lower than the previously reported data.     

Zirconium Determination by ED-XRF: a Critical Evaluation of Silicate Reference Materials as Calibration Standards

An assessment of the difficulties in determining zirconium by various techniques indicates that X-ray fluorescence analysis has several favourable characteristics, provided the technique can be calibrated reliably. After critical evaluation, a group of silicate reference materials was selected to calibrate energy dispersive X-ray fluorescence instrumentation. The accuracy of the resultant calibration was verified by a standards addition procedure. New zirconium data were obtained on a wide range of reference samples and compared with values from recent compilations.     

Reference samples for the earth sciences

A revised list of reference samples of interest to geoscientists has been extended to include samples for the agronomist, the archaeologist and the environmentalist. In addition to the source from which standard samples may be obtained, references or pertinent notes for some samples are included.The number of rock reference samples is now almost adequate, and the variety of ore samples will soon be sufficient. There are very few samples for microprobe work. Oil shales will become more important because of the outlook for world petroleum resources. The dryland equivalent of a submarine basalt might be useful in studies of sea-floor spreading and of the geochemistry of basalts.The Na- and K-feldspars of BCS (British Chemical Standards—Bureau of Analysed Samples), NBS (National Bureau of Standards), and ANRT (Association Kationale de la Recherche Technique) could serve as trace-element standards if such data were available. Similarly, the present NBS flint and plastic clays, as well as their predecessors, might be useful for archaeological pottery studies. The International Decade for Ocean Exploration may stimulate the preparation of ocean-water standards for trace elements or pollutants and a standard for manganese nodules.     

Determination of Radium-226 in CCRMP Reference Samples by Independent Nuclear Methods

Radium-226 concentrations have been determined in 11 CCRMP reference rock and ore samples using instrumental gamma-ray spectrometry and radiochemical radon emanation procedures. Results are compared to the best available data.