Ion probe measurements of National Institute of Standards and Technology standard reference material SRM 610 glass, trace elements

Abstract

Ion microprobe measurements have been made of 22 trace elements in the National Institute of Standards and Technology (NIST) glass standard, standard reference material SRM 610; this silicate glass standard nominally contains 500 ppm of 61 trace elements. Computer-controlled point-by-point analyses across 1 mm of a single glass fragment indicates that SRM 610 is homogeneous on a very small scale and that it can be used to check microanalytical precisions to at least 0.2%. Although it is not possible to exclude a single small volume differing from the average composition by a few per cent., there is no evidence for heterogeneity (except for F). It is likely that all variations observed in the analyses presented in this work are owing to instrument tuning effects. Variations observed between fragments of the SRM 610 glass obtained from a number of laboratories were essentially identical to those observed on a single fragment. Interlaboratory comparisons using different aliquots of the SRM 610 glasses do not introduce errors greater than 1%. SRM 610 can be considered homogeneous on the 10 µm–1 cm scale.