On the metrological traceability and hierarchy of stable isotope reference materials aimed at realisation of the VPDB scale: Revision of the VPDB δ13 C scale based on multipoint scale-anchoring RMs.

Multipoint-anchoring of the VPDB δ13 C scale provides several distinct "points" on the scale as means for cross-measurements to check the stability and viability of RMs and detect drift of values, if any. This ensures that the δ13 C scale is suitable for the most demanding applications, and provides options for developing further RMs with high accuracy inside a robust scale realisation scheme.