AX-R07 — Declared gravimetric mass balance does not close

Everything in the vial weighs something. Water, counter-ion, peptide, residual solvent and inorganic residue are exhaustive and mutually exclusive categories, and they must sum to the mass of the cake.

When a certificate declares 4.0 % water, 3.5 % acetate and 98.0 % peptide content, it has declared 105.5 % of the vial. One of those three numbers is wrong, or one of them is being reported on a different basis — most commonly, peptide content reported on an anhydrous, salt-free basis while water and counter-ion are reported as-is. That is a legitimate convention and it is why the rule allows 1.0 pp of slack and why the index's own records state the basis explicitly on every content figure.

Beyond 1.0 pp the certificate is not reconcilable without additional information that the certificate does not supply.

The index publishes its own mass balance on every record where the four measurements exist, closed to within 0.02 pp by construction, precisely so that a reader has something to compare a supplier's declaration against.