The research project for the preparation of two polymetallic nodule (GSPN‐2, GSPN‐3) and two marine sediment (GSMS‐2, GSMS‐3) reference materials was completed in 1996. The samples were collected from the Eastern and Central Pacific Ocean and prepared to less than 74 μm fine powder. The homogeneity of the materials was tested by X‐ray fluorescence spectrometry. The relative standard deviations (RSD %) of measurements of selected elements in samples taken from thirty bottles selected at random were less than 0.5%. Thirty four laboratories worldwide participated in the collaborative analysis programme. The number of elements or constituents analysed was seventy nine for nodules and eighty one for sediments. Among those, sixty three elements were certified in each sample. The sum of major elements or components is 99.7% for GSPN‐2, 99.5% for GSPN‐3, 99.8% for GSMS‐2 and 99.8% for GSMS‐3.
Four sulfide mineral reference materials, pyrite GSM‐1, chalcopyrite GSM‐2, galena GSM‐3 and sphalerite GSM‐4, have been prepared by the Institute of Rock and Mineral Analysis for collaborrative studies on their chemical composition. This paper describes the sample collection, preparation, homogeneity testing and interlaboratory certification of these samples. Some features with regard to the purification, pulverisation, stability and storage of sample are also discussed. The samples have been approved as certified reference materials by the State Bureau of Technical Supervision of China in April 1995.
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