(a) Reproducibility and accuracy for repeated measurements of 87
Sr on 12 ng load size of NSIT-SRM987 standard material for static versus dynamic collection mode over a period of 10 months. Each single measurement is plotted with the relative error bars. The grey-shaded field shows the [59
] recommended value range. (b) Distribution of the 87
Sr values measured all over the period of analysis with the static and dynamic collection mode: the static collection mode (black filled columns) shows a worst external reproducibility than that obtained in the dynamic mode (open columns); indeed the dynamic mode gives measurements that reasonably fit a Gaussian distribution pattern with the more representative 87
Sr values centered within the [59
] recommended interval (grey shade fields); (c) reproducibility and accuracy trend of 87
Sr 12 ng load size of NSIT-SRM987 measured in the dynamic collection mode throughout the setup period (from 2014 to 2016).