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Purity, identity and sterility are separate questions

A clear framework for reading the scope of an analytical result.

4 min readPublished 31 October 2026Editorial profile: Nina Fischer

Purity: what was detected under this method?

A chromatographic purity result describes the response observed using a particular analytical method. Record the stated method and how the laboratory expresses its result. Do not infer net peptide content or every possible contaminant measurement from a single percentage.

Identity: does the evidence support the named material?

Read the identification method, sample description and laboratory interpretation. A purity figure alone cannot resolve a mismatch between the named material and the tested sample.

Microbiological testing is a separate scope

Sterility and endotoxin testing address different questions from chromatographic purity. Check which tests were ordered and what the report actually covers. A provider offering multiple services has not necessarily performed all of them on a given sample.

Translate uncertainty into an action

List the unanswered procurement question and ask the laboratory which test can address it. Keep research documentation separate from decisions about medical care or administration.

Sources & further reading

  1. MZ Biolabs stated testing limitations ↗
  2. Janoshik separate test categories ↗
  3. Agilent peptide analysis resource ↗
Sources consulted 31 October 2026. This is a general documentation guide, without qualified clinical or regulatory review. See the research disclaimer.

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Who prepares these guides?

The PepSonar Editorial Team organizes public-source information and primary references. These guides have not undergone a qualified clinical or regulatory review.

Do these guides recommend a treatment?

No. They cover research procurement, certificates of analysis and the limits of analytical information. They do not provide dosing, administration instructions or personal medical advice.

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Nina Fischer
EDITORIAL PROFILE

Nina Fischer

Peptide Quality & Evidence Editor

I focus on peptide quality documentation, third-party testing, and the science behind product claims. I help readers understand COAs, research limitations, and the warning signs that deserve a closer look.

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