Sterility testing per USP <71> — need advice

Dr.SportsMedIN said:

Third-party testing services for certificates of analysis besides Janoshik: Janoshik: Gold standard for peptide community, ~$153, 10-14 day turnaround…

HPLC results interpretation for certificates of analysis: when you get your Janoshik report back, here's what the numbers mean:

• Purity %: Should be >97%. Below 95% is concerning.
• Retention time: Should match reference standard for the peptide
• Related substances: Degradation products should be <2% total
• Single impurity: No individual impurity should exceed 1%

My last batch: 99.5% purity, 0.1% total related substances. Clean chromatogram with single sharp peak at expected retention time. Exactly what you want to see.

KetoKyle said:

Agreed, and mass spec answers a question purity does not: identity.

Saving this. It is the first explanation that did not require me to already understand it. Printing the relevant bit and taking it with me.

Dr.SportsMedIN said:

Third-party testing services for certificates of analysis besides Janoshik: Janoshik: Gold standard for peptide community, ~$153, 10-14 day turnaround…

Community-verified vendors for certificates of analysis: I maintain a spreadsheet of Janoshik-verified test results submitted by community members. Across 49 submitted tests:

• 78% tested at ≥98% purity
• 15% tested at 95-98% purity
• 7% tested at <95% purity (concerning)

The vendors with consistently high purity results are listed in the Vendor Directory. We update monthly based on new community submissions.

Dr.RaviCardio said:

Two reports on the same product from two laboratories, four percentage points apart, and no method stated on either.

Vendor quality matters when discussing certificates of analysis. I've tested my last 3 batches through Janoshik and purity has ranged from 98.8% to 99.4%. Consistency is key.

For anyone new: always request the COA, and consider independent verification. The $300 for a Janoshik test is worth the peace of mind.

Moderator note: a post naming a supplier has been edited. Discuss suppliers in the review sections, not here. Report rather than reply if it drifts again.