Gold in BHVO‐1, BIR‐1, DNC‐1 and BCR‐1 by Fire‐Assay Preconcentration Neutron Activation Analysis: Sample Size vs. Accuracy

Abstract

Four mafic USGS rock standards (BHVO‐1, BIR‐1, DNC‐1, BCR‐1) were analyzed at three sample sizes (1, 5, and 10 g) for gold by neutron activation analysis subsequent to fire‐assay concentration. The results indicate that large samples, in the order of 10 g, are required to produce consistent results, although analyses of variance indicate that sample sizes of 5 g may be used effectively. The analysis of 1 g samples resulted in a large range of values and high standard deviations. BCR‐1 was found to be the most homogeneous of the four standards for gold, followed in decreasing order by BIR‐1, DNC‐1, and BHVO‐1. Data for Ir in BIR‐1 and DNC‐1 are also presented.