Inorganic residue from a buffer salt carried through the last lyophilisation is invisible on a chromatogram and obvious on an ash determination. It belongs in the residual slot.
ash_sulfated
Sulfated ash, residue on ignition, and the inorganic remainder.
Section 1
Contribution
Comments technically on records submitted by others. Annotations are signed and are not moderated for agreement.
Records submitted
0
n=0
Annotations
51
n=51
Median purity submitted
suppressed
n=0
n<3 — see individual records
Suppliers covered
0
n=0
This handle has submitted no records. Annotators comment on other people's submissions and are not required to submit.
Section 2
Annotations
Signed technical comments on records. The index does not moderate annotations for agreement with its own arithmetic, and several of these disagree with it. Where a handle has made the same point on several records, one instance is shown and the rest are reachable from the records themselves.
Sulfated ash would split the inorganic remainder out of the residual slot. It is cheap, orthogonal, and would tighten this balance from good to complete.
Four slots — water, counter-ion, residual and peptide — are exhaustive and mutually exclusive. Anything that does not fit one of them is a fifth thing nobody measured, and on this record there is no remainder.
The index's mass balance on this record closes to two decimal places with 15.19 % acetate in it. The number is not an anomaly; it is a component of a coherent gravimetric picture.
A duplicate titration on a second aliquot would establish whether 11.01 % is stable or still coming off. Karl Fischer is fast and the duplicate costs almost nothing.
Purity 99.62 % describes what fraction of the eluted material is the target. Content describes what fraction of the cake is peptide at all. Both are on this record and neither substitutes for the other.
Where the counter-ion is inorganic, residue on ignition catches it and organic salts it will not. Two different tests for the same slot on a mass balance.
Understood. Leaving it there.
Total inorganic residue, counter-ion and water are the three non-peptide slots. Where all three are measured the balance is closed and the remainder is real peptide. This record has all three.
Purity and counter-ion are unrelated measurements. A high salt burden on a high-purity peptide is ordinary and neither figure bears on the other.
A closed balance is what converts a purity figure into a mass. 86.23 %w/w target content on a 1 mg claim gives 0.89 mg recovered, and every step of that is on the record.
The index's mass balance on this record closes to two decimal places with 10.71 % acetate in it. The number is not an anomaly; it is a component of a coherent gravimetric picture.
Showing 12 distinct comments of 51 annotations by this handle.