Acetate against trifluoroacetate changes the peptide mass fraction of the cake by several points at the same molar loading. Salt form is a real economic variable and it is almost never on the label.
acetate_only
Salt-form preference and its effect on recovered peptide mass per vial.
Section 1
Contribution
Both submits records and annotates other people's.
Records submitted
6
n=6
Annotations
22
n=22
Median purity submitted
99.35%
n=6
Suppliers covered
5
n=6
Section 2
Records submitted
A submitter chose to buy this material and to pay for this assay. That choice is the selection mechanism behind the whole index and it is not random.
| Report | Compound | Supplier | Lot | Lab | Quarter | Purity % | Water % | Recovery % | Provenance | Flags | Result |
|---|---|---|---|---|---|---|---|---|---|---|---|
| AX-2026-041395 | Oxytocin | QYB | QYB-2601-V4429 | Janoshik | 2026-Q2 | 99.93 | 4.24 | 101.7 | Buyer-sourced | 0 | PASS |
| AX-2026-042911 | Selank | GGPeps | GGPE-2601-J3130 | Kestrel | 2026-Q2 | 99.37 | 9.99 | — | Buyer-sourced | 0 | PASS |
| AX-2026-042898 | BPC-157 | GGPeps | GGPE-2602-N2621 | VendorInvestigate | 2026-Q2 | 98.94 | 5.47 | 94.4 | Buyer-sourced | 1 | MARGINAL |
| AX-2025-018464 | Tirzepatide | WWB | WWB-2506-T2732 | Janoshik | 2025-Q4 | 99.08 | 3.36 | 106.7 | Buyer-sourced | 0 | PASS |
| AX-2024-004466 | Semax | AMB | AMB-2411-G5528 | Janoshik | 2024-Q4 | 99.82 | 9.01 | — | Buyer-sourced | 0 | PASS |
| AX-2024-004524 | ARA-290 | HYB | HYB-2403-B7301 | Janoshik | 2024-Q3 | 99.33 | 7.74 | — | Buyer-sourced | 0 | PASS |
Section 3
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.
Salt form affects hygroscopicity as well as mass. Acetate cakes generally pick up less water than trifluoroacetate ones, which shows up in the water column rather than this one.
The index's mass balance on this record closes to two decimal places with 10.95 % TFA in it. The number is not an anomaly; it is a component of a coherent gravimetric picture.
A shift in salt form between lots changes the recovered peptide per vial without changing anything about the peptide. Worth checking before reading a recovery difference as a quality difference.
Acetate is preferred at scale for handling and for downstream compatibility. A shift from TFA to acetate between lots is a process change and it moves the recovered-mass arithmetic.
The index's mass balance on this record closes to two decimal places with 26.54 % citrate in it. The number is not an anomaly; it is a component of a coherent gravimetric picture.
Seconded.
Showing 7 distinct comments of 22 annotations by this handle.