Bachem vs GenScript documentation: useful methods, no lot-level winner

Our verdict on the resources

GenScript explains HPLC peak-area reporting and mass spectrometry, and states that it provides a certificate of analysis, MS and HPLC validation data for each peptide. Its diagrams make the public guide a useful first reading assignment for someone unfamiliar with the reports. That statement is the supplier's description of its service, not our verification of a delivered lot. [1]

Bachem's quality-control guide covers several different analytical questions, including identity and peptide-content measurements. We prefer it as a prompt for asking what a headline purity percentage leaves unanswered. Its breadth is educational; it does not establish that every listed analysis is supplied for every product. [2]

Our criticism of both as purchasing evidence is the same: a general methods page cannot authenticate the specific document in your inbox. A good explanation of analytical methods is worth reading, but it does not close a procurement review.

Compare the evidence, not the brand names

A lower percentage can still be the better document packet

Consider two invented offers. Packet A says 99% purity but has no lot identifier and no method attachment. Packet B says 97% chromatographic purity, names its lot and method, and provides the corresponding report. We would advance B for technical review and request clarification on A. That is a judgment about reviewability, not a finding that B is chemically better or acceptable for use.

If the laboratory specification requires a threshold neither packet demonstrates, both remain unresolved. Do not relax that specification because B supplied more paperwork. A documentation comparison should be able to end with no acceptable candidate.

Where traceability changes the discussion

NIST treats metrological traceability as a property of a measurement result, and explicitly says it does not automatically establish fitness for purpose. Our editorial preference is to ask for the measured property and relevant uncertainty before accepting an impressive reference-standard name. [3]

For a procurement comparison, separate the document you can inspect, the issuer claim you have not independently authenticated, and the laboratory's acceptance decision. A claim can be present in the packet and still remain unverified. Preserve that distinction instead of awarding a numerical trust score.

Who should use this review, and who should skip it

Use it to prepare questions for a laboratory procurement or quality team. Skip it as a buying recommendation for personal use: we have not purchased, independently analyzed or audited materials from either company. These analytical resources do not establish human-use safety or clinical benefit.

The practical next step is a lot-specific document request based on your laboratory's approved requirements. Keeping an existing qualified source, postponing a purchase, or requesting independent analysis through the laboratory process are valid alternatives to selecting a new seller. Public resources were reviewed on 20 September 2026.