LC-MS/MS vs HPLC for peptide analysis — which is more reliable?

Dr.ReproEndo said:

Vendor quality matters when discussing certificates of analysis.

This matches mine closely enough to be worth saying so out loud.

FDA_TrackerJim said:

I tested my certificates of analysis batch through Janoshik — 98.4% purity.

Second this. Nothing to add that would improve it.

FDA_TrackerJim said:

I tested my certificates of analysis batch through Janoshik — 98.4% purity.

COA red flags for certificates of analysis — here's what to look for when reviewing a Certificate of Analysis:

• No HPLC data: If there's no chromatography graph, it's not a real COA
• Exact 100% purity: Suspicious — real testing always shows slight variation
• No batch number: Can't trace back to specific production
• No endotoxin testing: For injectables, this is essential
• Template looks like it was made in Word: Professional labs have standardized formats

I have seen fake COAs that are literally photoshopped. Always verify independently if possible.

FDA_TrackerJim said:

I tested my certificates of analysis batch through Janoshik — 98.4% purity.

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, 0.2% total related substances. Clean chromatogram with single sharp peak at expected retention time. Exactly what you want to see.

Moderator note: two posts asking for a source have been merged into one. Please search the thread before asking again. Tagging this one for the weekly digest.