Kennecott Standard GRLD-126 manganese nodule replicate Atomic absorption spectrophotometry (AAS) analyses

The Kennecott nodule standard GRLD-126 was run with several batches of the nodule structure zone samples in order to check the precision of the atomic absorption analyses. Using the standard deviation as a measure of precision, copper values are the most reproducible (+- 4% from the mean), with manganese (+- 5%), nickel (+- 6%), iron (+- 7%) and cobalt values (+- 14%) being successively less precise. The possible variability of the cobalt values is such that subtle differences in cobalt content between many oxide crusts and subcrusts may not be real.