Changing the ion-pairing additive changes selectivity on charged sequences more than changing the column does. It is the first thing to try on a stubborn close pair.
ion_pair_ip
Ion-pair reagents for charged and short peptides.
Section 1
Contribution
Both submits records and annotates other people's.
Records submitted
8
n=8
Annotations
62
n=62
Median purity submitted
98.88%
n=8
Suppliers covered
8
n=8
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-2026-042603 | Semaglutide | HJ | HJ-2608-C7002 | Janoshik | 2026-Q3 | 99.16 | 3.42 | 105.9 | Buyer-sourced | 0 | PASS |
| AX-2026-043344 | Leuprolide | WXT | WXT-2604-K2596 | Janoshik | 2026-Q3 | 98.58 | 5.34 | — | Buyer-sourced | 0 | PASS |
| AX-2026-043278 | L-Glutathione (reduced) | CPC | CPC-2602-D1499 | Janoshik | 2026-Q1 | 98.23 | 7.31 | 93.2 | Buyer-sourced | 0 | FAIL |
| AX-2026-043109 | Epitalon | KP | KP-2508-Y5884 | Janoshik | 2026-Q1 | 98.39 | 8.24 | 99.8 | Buyer-sourced | 0 | FAIL |
| AX-2025-020378 | PT-141 (Bremelanotide) | MKM | MKM-2509-B4043 | PeptideMeter | 2025-Q4 | 99.43 | 6.01 | — | Buyer-sourced | 0 | PASS |
| AX-2025-020722 | BPC-157 | SGN | SGN-2507-F9360 | Kestrel | 2025-Q3 | 98.59 | 4.83 | 106.2 | Buyer-sourced | 0 | PASS |
| AX-2025-019286 | Semax | AMB | AMB-2411-G5528 | Medutest | 2024-Q4 | 99.53 | 9.78 | — | Buyer-sourced | 0 | PASS |
| AX-2024-004184 | Kisspeptin-10 | WWB | WWB-2311-T3203 | Janoshik | 2024-Q2 | 99.93 | 6.41 | — | 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.
Purity 99.74 % with Ala-Glu-Asp tripeptide (−57 Da) at 0.19 % nearby. Read the pair together: the purity figure and its nearest neighbour are two views of one integration decision.
Ion-pairing additive concentration changes retention on charged sequences dramatically. A tenth of a percent against a twentieth moves peptides by minutes, in a direction that depends on charge.
Two laboratories with different gradients will resolve a close pair differently and report two honest, different purities. Neither is wrong and the difference is not a disagreement about the material.
Purity 99.06 % with acetyl adduct (+42 Da) at 0.37 % nearby. Read the pair together: the purity figure and its nearest neighbour are two views of one integration decision.
Retention is the cheapest orthogonal check on identity available and the one most often discarded. A flag here is worth following up precisely because the check is so nearly free.
The resolution figure sits in the system-suitability block with no PASS or FAIL beside it. That is deliberate: the index reports it and adjudicates nothing against it.
Nothing on this record is flagged for resolution and nothing will be. The figure exists so the reader can weight the purity number, which is its only purpose.
Purity 98.27 % with zuclomiphene (cis-isomer) at 1.15 % nearby. Read the pair together: the purity figure and its nearest neighbour are two views of one integration decision.
Purity 99.10 % with tBu-protected residual (+56 Da) at 0.61 % nearby. Read the pair together: the purity figure and its nearest neighbour are two views of one integration decision.
Showing 10 distinct comments of 62 annotations by this handle.