How Pure Helix analytical testing works
Every released lot carries an independent certificate of analysis. This page explains what is measured, how each result is produced, and — just as importantly — what each measurement does not establish.
- Last scientific review
- September 2026
- Published by
- Pure Helix
Why lot-level testing, not batch marketing
A purity figure printed on a category page describes nothing in particular. A purity figure tied to a lot number describes a specific quantity of material that was weighed, filled and sealed together, and that can be traced from the vial in a researcher's hand back to the chromatogram that characterised it.
Pure Helix therefore publishes results per lot. The lot identifier appears on the vial label, on the product page for the size in question, and on the certificate itself. Where a lot's certificate has not yet returned from the laboratory, the listing says so rather than borrowing a neighbouring lot's result.
What gets measured
- Identity — confirmation by mass spectrometry that the observed molecular mass matches the expected mass of the declared compound.
- Purity — reversed-phase HPLC with UV detection at 214 nm, reported as the percentage of total integrated peak area attributable to the main peak.
- Content / quantitation — how much of the declared compound the vial actually contains, reported in milligrams against the labelled fill.
- Appearance and solubility — visual conformance of the lyophilised cake and its behaviour on reconstitution.
How to read the numbers we publish
Two figures appear on Pure Helix certificates and are easy to conflate. Purity is a relative measurement: it describes the proportion of the detected material that is the target compound. Content is an absolute measurement: it describes how many milligrams of that compound are present in the vial.
A lot can be highly pure and still be over- or under-filled, and a lot can be filled accurately while containing related substances. Both numbers are needed, which is why both are printed.
| Reported field | Method | What it establishes | What it does not establish |
|---|---|---|---|
| Identity | Mass spectrometry | The observed mass is consistent with the declared molecule | Nothing about how much is present, or about impurity profile |
| Purity % | RP-HPLC, UV 214 nm | Proportion of UV-detectable material that is the main peak | Presence of species that do not absorb at 214 nm or do not elute |
| Content (mg) | HPLC quantitation against a standard | Absolute mass of target compound in the vial | Purity, sterility, or stability over time |
Lot identifiers
Pure Helix lot numbers follow the pattern PH + YYMM + a sequence number, where YYMM is the year and month of testing. PH260802, for example, is the second lot recorded in August 2026. The sequence digits are a register position, not a calendar day.
Scope and limits
Analytical testing characterises material. It does not make material safe, and it says nothing about biological activity in any organism. Certificates describe the sample the laboratory received, at the date on the report. Results are not a specification for use in humans or animals, and Pure Helix makes no such claim.
Pure Helix supplies materials for laboratory research use only. Nothing on this page is medical advice, and none of the material described is for human or veterinary use.
Primary literature and standards
- ICH Q2(R2) — Validation of Analytical ProceduresFramework for specificity, accuracy and precision in analytical method validation.
- ICH Q6B — Specifications: Test Procedures and Acceptance Criteria for Biotechnological/Biological ProductsReference framework for identity, purity and quantity testing of peptide and protein material.
In this research cluster
- Analytical TestingHPLC peptide purity: what the percentage actually measuresPurity by HPLC is an area-percent measurement, not a statement that a vial is 99% target compound by mass. The distinction changes how the number should be used at the bench.
- Analytical TestingLC-MS peptide identity: mass confirmation versus purityHPLC asks how much of the detected material is one species. Mass spectrometry asks whether that species is the molecule on the label. Neither substitutes for the other.
- Analytical TestingHow to read a peptide certificate of analysisA certificate is a record of one sample on one date by one method. Read in that order, it is informative; read as a badge, it is nearly meaningless.
- Laboratory MethodsLyophilised peptide stability and degradation pathwaysDegradation in peptide reference material is not a single process. The literature separates chemical routes from physical ones, and they respond differently to storage conditions.
Related reading
- Compound ResearchRetatrutide research hubRetatrutide is a synthetic 39-residue peptide reported to engage three incretin-family receptors. This hub collects the mechanism pages, the molecular reference record and the lot documentation in one place.
- Compound ResearchTirzepatide research hubTirzepatide is the reference dual incretin agonist. Its characterisation literature is unusually explicit about receptor imbalance and biased signalling, which is what makes it useful at the bench.