Analysis and release
HPLC tested peptides, UK
Every batch is assayed before it is offered for sale, and the figures we measure are published with the material. Below is exactly which methods we run, what each one detects, and — the part most suppliers leave out — what each one cannot see.
Batch RYZ-RETA-26071 · retatrutide
A released trace: one dominant peak, small related substances resolved to baseline either side of it. This is what the specification looks like when it is met.
Four determinations
What we measure, and what it can miss
No single method characterises a peptide. Each of these answers a different question, and the blind spots of one are covered by another.
Purity
Reversed-phase HPLC
Gradient elution on C18, UV detection at 214 nm, reported as area percent. 214 nm is where the peptide bond absorbs, so every peptide species in the sample is visible — including the ones that carry no aromatic residues and would be invisible at 280 nm.
- Detects
- Related substances, deletion sequences, oxidised species, dimers.
- Cannot see
- Anything that does not absorb or does not elute — salts, water, counter-ion. And identity: a single peak proves homogeneity, not that the material is correct.
Identity
Electrospray ionisation mass spectrometry
Observed average mass compared against the theoretical value calculated from the sequence. Discrepancies are diagnostic rather than merely disqualifying — 16 Da high is oxidation, 42 Da is acetylation, a residue-sized gap is a deletion sequence.
- Detects
- Wrong compound, wrong modification state, deletion sequences that co-elute with the target.
- Cannot see
- Isomers. Leucine and isoleucine weigh the same; so does a D-amino acid substitution. Intact mass does not confirm sequence order.
Water content
Karl Fischer coulometric titration
A titration specific to water. Residual moisture affects both stability and the concentration you calculate from vial weight, and hygroscopic compounds can gain measurable mass in minutes on an open bench.
- Detects
- Under-dried material, and vials that have taken up moisture in handling.
- Cannot see
- Solvents other than water.
Counter-ion
Ion chromatography
Peptides leave reversed-phase purification as a salt. We supply acetate rather than trifluoroacetate wherever the chemistry allows, because TFA is cytotoxic at concentrations that occur in ordinary cell culture.
- Detects
- Excess counter-ion loading, and TFA where acetate was specified.
- Cannot see
- Nothing relevant to this determination.
Release specification
The thresholds material has to clear
These are the standing limits. Individual compounds carry tighter specifications where their chemistry demands it, and the specification for each line is stated on its product page.
Material outside specification is rejected. There is no lower grade to sell it at.
- Purity, peptides
- ≥ 99.0% area (RP-HPLC)
- Purity, long sequences
- ≥ 98.0% area (RP-HPLC)
- Purity, non-peptide compounds
- ≥ 98.0% area (HPLC)
- Mass agreement
- Within instrument tolerance
- Water content
- ≤ 8.0% (Karl Fischer)
- Residual acetate
- ≤ 8.0%
- Single related substance
- ≤ 0.5% area
- Appearance
- Conforms to reference
- Retest interval
- 24 months from release
Who signs it off
Release is a person, not a checkbox
Every batch is dispositioned by someone who has read its chromatogram and its spectrum. The certificate carries their authorisation.
Analytical release
Reviews every chromatogram and spectrum against specification before disposition.
Incoming reconciliation
Matches each consignment to its manufacturing record before it enters quarantine release.
Fill verification
Gravimetric check on fill weight, inert headspace, and batch code applied to the vial.
Published release data
Recent batches
Current and recent stock, with the measured figures. Read the certificate before you order, not after.
| Batch | Material | Purity | Water | Released | |
|---|---|---|---|---|---|
| RYZ-BPC1-26081 | BPC-157 | 99.4% | 4.0% | 12 Aug 2026 | Certificate |
| RYZ-NADP-26081 | NAD+ | 98.9% | 5.8% | 05 Aug 2026 | Certificate |
| RYZ-MOTS-26073 | MOTS-c | 99.2% | 4.2% | 28 Jul 2026 | Certificate |
| RYZ-ACSX-26072 | N-Acetyl Semax Amidate | 99.6% | 3.3% | 21 Jul 2026 | Certificate |
| RYZ-EPIT-26071 | Epitalon | 99.2% | 4.4% | 16 Jul 2026 | Certificate |
| RYZ-RETA-26071 | Retatrutide | 99.6% | 3.1% | 14 Jul 2026 | Certificate |
Questions
About the testing
Technical questions reach the analytical team rather than a sales inbox.
- Are your peptides third party tested?
- Yes. Batches are assayed at an independent contract laboratory in addition to the manufacturer's own release testing. Where an independent result is available it is the figure reported on the certificate, and the certificate names the laboratory.
- What does HPLC tested actually mean?
- It means purity was determined by gradient reversed-phase HPLC with UV detection, reported as the area of the main peak as a percentage of total peak area. The detail that matters is the gradient and the wavelength: a steep gradient merges impurities into the main peak, and 280 nm detection misses any species without aromatic residues. We run a shallow gradient at 214 nm and state both on the certificate.
- Why do you report water content?
- Because it changes your concentration calculation. A vial at 8% water contains measurably less peptide per milligram of powder than one at 3%. Certificates that omit water content on a hygroscopic compound leave you unable to calculate accurately.
- What happens to material that fails specification?
- It is rejected. It is not sold at a lower grade, relabelled, or blended into a compliant batch. Where a related species is present but within specification, it is reported as its own line on the certificate rather than folded into a single purity figure.
- Can I see the certificate before I order?
- Yes. Every released batch is published to the certificate library, so you can read the actual release data for current stock before buying. After delivery, the batch code on your vial looks up the same document.
- Do you provide the chromatogram, not just the number?
- Yes. The trace is on the certificate. A number can be typed; a trace shows whether impurity peaks were resolved to baseline or hidden on the shoulder of the main peak, which is where inflated figures live.
