ISSN:0150-5505    

DOI:10.1111/j.1751-908X.1991.tb00089.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

The concentrations of numerous constituents must be evaluated in rock samples if they are to be used as reference materials. Because of varying degrees of specialized skills in earth‐science laboratories, the collaboration of many institutions is required in order to establish reliable values. Analytical data reported in such operations are highly variable. The number of constituents reported per sample varies from one laboratory to another. The number of values reported varies from one constituent to another. The reported values for each constituent are generally incoherent, often displaying skewed distributions. The problem is then how to deduce the most probably “true’ concentration for each constituent. Various computation schemes, based on medians, means and related measures, are discussed. A new scheme, involving a combination of modes, is pro

ISSN:0150-5505    

DOI:10.1111/j.1751-908X.1991.tb00090.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Two principal approaches are being used currently to develop reference samples used in geochemistry. The first is typified by work at The National Institute of Standards and Technology (NIST) to develop standard reference materials (SRMs) whose elemental concentrations are certified. All data is collected under stringent quality control (QC). Agreement between average results for replicated analyses (6≤n<20) obtained by two or more analysts using either a single, definitive method or independent methods of analysis is required for certification; a large number of laboratory/method average results is not. The United States Geological Survey (USGS), International Working Group (IWG), and others base recommended concentrations on larger sets of compiled data, which may or may not have been collected under similar conditions of QC. The derived recommended concentrations are updated periodically, on the assumption that recommended concentration quality improves as the size of the data base increases. That assumption is examined in this paper, and the general lack of statistically significant difference between original and updated concentration is demonstrate

ISSN:0150-5505    

DOI:10.1111/j.1751-908X.1991.tb00091.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

The role played by geochemical reference materials in establishing and maintaining a quality control/quality assurance program in a geochemical/assay laboratory is discussed. It includes the development of in‐house reference materials and their characterization with reference to internationally recognized reference materials. It also concerns reference materials for use in geochemical trace analysis, ore grade assays and the analysis of concentrates for establishing the values of shipments. Suggestions are given for the sources and preparation of various types of reference materials that may need to be developed for in‐house

ISSN:0150-5505    

DOI:10.1111/j.1751-908X.1991.tb00092.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

A critical aspect of any quality control program is the definition of criteria for “satisfactory’ performance of analytical methods. These criteria should address both expected accuracy and expected precision of the methods, as well as any variation in these figures of merit from one sample type to another. Development of appropriate criteria and their application to analytical programs for the characterization of new reference samples is presen

ISSN:0150-5505    

DOI:10.1111/j.1751-908X.1991.tb00093.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Data for as many as 31 elements were determined by instrumental thermal neutron activation analysis for nine European Council for Mutual Economic Assistance (CMEA) rock and ore standards. The National Bureau of Standards plastic clay 98 and the University of Gent fired clay FCG were also analyzed. Synthetic, multielement standards were used and USGS rock standards provided reference samples. Correction factors for uranium fission products on cerium and molybdenum, and also for less commonly encountered spectral interferences, such as those due to the 213 ppm tantalum in granitoid 2B, were evaluated.

ISSN:0150-5505    

DOI:10.1111/j.1751-908X.1991.tb00094.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

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 demonstra

ISSN:0150-5505    

DOI:10.1111/j.1751-908X.1991.tb00095.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Analysis of 24 reference materials for B, Sm, Gd, H, has been carried out over several years, using prompt gamma neutron activation analysis. The results are compared with values obtained by other workers, in order to better calibrate these standards. In most cases our results of repeated analysis of RMs show agreement with results from other laboratories, using various methods. A djustments to working values are proposed in some cases.

ISSN:0150-5505    

DOI:10.1111/j.1751-908X.1991.tb00096.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Brief description of seven magmatic rock reference samples (DV series), analytical methods employed and certified values for major, minor and trace elements are presented.

ISSN:0150-5505    

DOI:10.1111/j.1751-908X.1991.tb00097.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Brief description of four sedimentary rock reference samples (GPOS series), information on analytical methods employed and certified values for major, minor and trace elements are presented.

ISSN:0150-5505    

DOI:10.1111/j.1751-908X.1991.tb00098.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY