Determination of Trace Elements Across Annual Ring Structure of Ferromanganese Nodule by Laser Ablation-ICP-MS

Abstract

Trace elements were determined across the annual ring structures of a ferromanganese nodule by laser ablation/inductively coupled plasma mass spectrometry (LA-ICP-MS). The determined values were obtained from 30 points by spatial-resolution analysis using LA-ICP-MS. The ferromanganese nodule was also sampled by hand-picking, and the samples were determined by ICP-MS in order to compare the determined values by LA-ICP-MS. With internal standard corrections using Mg or Mo, the determined values by LA-ICP-MS were in good agreement with those by ICP-MS. LA-ICP-MS verified that the Fe concentration increased with increasing Co and REE concentration in a ferromanganese nodule. This fact seemed to indicate that the determined values by LA-ICP-MS were acceptable. Furthermore, the variation of a cerium anomaly across the annual ring structure was verified by LA-ICP-MS. A positive cerium anomaly was observed at the points where Fe was enriched. From these results, the determination method for a spatial-resolution analysis of a ferromanganese nodule using LA-ICP-MS was developed and achieved.