Has anyone dealt with janoshik vs in-house testing?

From the other side of the consultation, briefly.

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: 99.6% purity, 0.0% total related substances. Clean chromatogram with single sharp peak at expected retention time. Exactly what you want to see.

Following on from ZaraB_AL — and this may be the naive question:

Was that from a primary source or from a summary of one?

ingrid_STO said:

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

Vendor quality matters when discussing certificates of analysis. I've tested my last 3 batches through Janoshik and purity has ranged from 99.6% 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.

ingrid_STO said:

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

Reconstituted peptide stability data for certificates of analysis: I had Janoshik test my reconstituted vial at day 1, day 14, and day 28 stored in the refrigerator.

Day 1: 99.6% purity
Day 14: 98.4% purity
Day 28: 99.2% purity

Minimal degradation over 28 days when properly refrigerated. This confirms the standard 28-day beyond-use date is appropriate. Beyond 28 days, I'd reconstitute a fresh vial to be safe.

Moderator note: two posts asking for a source have been merged into one. Please search the thread before asking again. No action needed from anybody.