Jean-François HélieUQAM - Geotopδ13C values are expressed relative to VPDB defined by the calcite standard NBS19 in the 1980s. To improve interlaboratory consistency a second anchor (lithium carbonate, LSVEC) was introduced in 2006 which is now known to be isotopically unstable. With the new reference materials made available by IAEA in 2020, it is now possible to realize the VPDB independently from LSVEC. It has recently been shown that using NBS19 & LSVEC or ...