Flow rate is the free variable most operators never touch. Halving it on an isocratic hold across the pair is a fifteen-minute experiment with a definitive answer.
hplc_ola
Method development chemist. Twelve years on peptide RP-HPLC. Will always ask for the gradient.
Section 1
Contribution
Both submits records and annotates other people's.
Records submitted
9
n=9
Annotations
133
n=133
Median purity submitted
98.49%
n=9
Suppliers covered
7
n=9
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-2026-041712 | Tirzepatide | TFS | TFS-{CAT}-1353 | VendorInvestigate | 2026-Q1 | 97.90 | 4.07 | 88.8 | Buyer-sourced | 1 | MARGINAL |
| AX-2025-019571 | Tirzepatide | TFC | TFC-2507-T1116 | PeptideMeter | 2025-Q3 | 97.47 | 3.59 | — | Buyer-sourced | 0 | PASS |
| AX-2025-020394 | Tirzepatide | MKM | MKM-2411-B3993 | Nordanalyt | 2025-Q2 | 98.49 | 5.12 | — | Buyer-sourced | 0 | PASS |
| AX-2025-020986 | ARA-290 | WXT | WXT-2502-N3730 | Janoshik | 2025-Q2 | 99.93 | 3.35 | — | Supplier-supplied | 1 | MARGINAL |
| AX-2025-019649 | GHRP-2 | TFC | TFC-2502-D2333 | Janoshik | 2025-Q1 | 99.40 | 4.89 | 93.8 | Buyer-sourced | 0 | PASS |
| AX-2024-004460 | Retatrutide | SinoPep | SNP-2405-T4694 | Medutest | 2024-Q4 | 98.06 | 4.26 | 106.8 | Buyer-sourced | 0 | PASS |
| AX-2024-004240 | GHRP-6 | QYB | QYB-2410-S4374 | Janoshik | 2024-Q4 | 99.48 | 6.40 | 106.3 | Buyer-sourced | 0 | PASS |
| AX-2024-004724 | Retatrutide | Homopeptide | HOMO-2405-B3923 | Medutest | 2024-Q3 | 97.83 | 6.10 | 101.2 | Buyer-sourced | 1 | FAIL |
| AX-2024-004636 | AOD-9604 | TFC | TFC-2402-L2242 | Kestrel | 2024-Q2 | 99.77 | 5.69 | 88.7 | Buyer-sourced | 1 | MARGINAL |
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.
Column temperature shifts selectivity by a few percent per ten degrees on peptides. Where two peaks are this close that is enough to matter and it is rarely on the report.
A longer gradient buys resolution on close-eluting pairs at a linear cost in run time. Janoshik ran 30 min here; the reference method runs 30, and the difference is visible in this figure.
Purity 98.34 % with truncated (2-39) at 1.04 % nearby. Read the pair together: the purity figure and its nearest neighbour are two views of one integration decision.
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.
A longer gradient buys resolution on close-eluting pairs at a linear cost in run time. Nordanalyt ran 35 min here; the reference method runs 30, and the difference is visible in this figure.
A longer gradient buys resolution on close-eluting pairs at a linear cost in run time. Kestrel ran 15 min here; the reference method runs 30, and the difference is visible in this figure.
A longer gradient buys resolution on close-eluting pairs at a linear cost in run time. Medutest ran 25 min here; the reference method runs 30, and the difference is visible in this figure.
Column temperature, mobile-phase additive concentration, and dwell volume. Three parameters, all uncontrolled between laboratories, all capable of moving a peak by more than the window.
A longer gradient buys resolution on close-eluting pairs at a linear cost in run time. PeptideMeter ran 28 min here; the reference method runs 30, and the difference is visible in this figure.
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.
Mobile-phase preparation is the unglamorous cause. Aqueous phase made up by volume against by weight shifts retention reproducibly and nobody records which was used.
Showing 12 distinct comments of 133 annotations by this handle.