andrew_nyc said: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…
Vendor quality matters when discussing certificates of analysis. I've tested my last 3 batches through Janoshik and purity has ranged from 97.4% to 99.0%. 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.
VanRx_Mike said:Agreed, and mass spec answers a question purity does not: identity.
Thank you — that is the clearest version of this I have read, and I have read a lot of them. I will report back once I have actually tried it.
andrew_nyc said: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…
My vendor review relevant to certificates of analysis: ordered 6 times from my current compounder. Consistency has been excellent.
Shipping: 3-day with temperature monitor
Packaging: Professional, discreet, proper labeling with lot/batch numbers
Purity: 98.7% average across orders (Janoshik verified)
Customer service: Responsive within 1 hours
Price: $127/month for tirzepatide 10mg equivalent
Sigma-Aldrich — Research-Grade Standards
Certified reference materials, analytical reagents, and research-grade standards for peptide verification. Trusted by laboratories worldwide.
Shop Reference Standardssarah_TO said:Two reports on the same product from two laboratories, four percentage points apart, and no method stated on either.
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: 99.4% purity, 0.0% total related substances. Clean chromatogram with single sharp peak at expected retention time. Exactly what you want to see.
Moderator note: good thread. Keeping it here rather than moving it, because the question is general enough to be useful. Report rather than reply if it drifts again.