How to Read a COA (Certificate of Analysis) for Research Compounds

Research Disclaimer: All compounds described are sold exclusively for in-vitro and laboratory research use. Not for unsupervised use. This content does not constitute medical advice.

A Certificate of Analysis (COA) is the primary quality document for any research compound. It summarizes the analytical testing performed on a specific production batch and reports whether the compound meets defined specifications. Knowing how to read a COA correctly — and what to look for — is one of the most important skills for any research compound purchaser.

COA Structure: What Every Document Should Include#

Essential sections:

1. Header information:

   • Compound name and/or CAS number
   • Batch/lot number (must be unique; every batch gets its own COA)
   • Testing laboratory name and location
   • Test date
   • Customer/supplier name (may be redacted for privacy)

2. Test results section:

   • HPLC purity result
   • MS identity result
   • Endotoxin result (if tested)
   • Appearance (color, physical form)
   • Other tests (water content, residual solvents, etc.)

3. Authorization:

   • Analyst signature or digital verification
   • QR code (Janoshik and other reputable labs include this for online verification)

Reading the HPLC Purity Result#

What you'll see:

Purity (HPLC, UV 214nm, area%): 99.1%

How to interpret it:

• This means 99.1% of the total UV-absorbing area in the chromatogram belongs to the target compound peak
• The remaining 0.9% represents other UV-absorbing compounds (impurities, degradation products)

What to check:

• Is the detection wavelength stated? (Should be 214–220 nm for peptides)
• Is the method stated? (RP-HPLC or HILIC; column type)
• Is the result ≥98%? (The standard minimum for research grade)
• Is a chromatogram image included? (Optional but useful — confirms the peak assignment)

Warning sign: A COA that states "Purity: 99%" without specifying the method, wavelength, or analytical technique is not a valid analytical document.

Reading the Mass Spectrometry Identity Result#

What you'll see:

Identity (ESI-MS): [M+2H]2+ observed 710.8 Da; expected 710.8 Da (BPC-157, MW 1419.56 Da) — PASS

How to interpret it:

• The instrument measured the [M+2H]2+ ion (the doubly protonated molecule) at m/z 710.8
• The expected value for BPC-157 is (1419.56 + 2) / 2 = 710.78 ≈ 710.8
• The measured and expected values match → compound is confirmed as BPC-157

For larger peptides (semaglutide, retatrutide):

• Multiple charge states may be reported: [M+4H]4+, [M+5H]5+, etc.
• All should match expected values derived from the compound's molecular weight

Critical check: If the observed m/z doesn't match the expected value for the claimed compound, the compound's identity is not confirmed — regardless of purity.

Reading the Endotoxin Result#

What you'll see:

Endotoxin (LAL test): <0.5 EU/mg — PASS

How to interpret it:

• The LAL (Limulus Amebocyte Lysate) test measures bacterial endotoxin levels
• EU/mg = Endotoxin Units per milligram of compound
• <0.5 EU/mg means less than 0.5 endotoxin units per milligram of peptide

Reference standards:

• In vitro use: ≤1 EU/mg generally acceptable
• In vivo use: ≤0.1 EU/mg recommended (endotoxins cause severe inflammatory responses in animals at very low doses)
• Injectable pharmaceutical standard: ≤0.25 EU/mL (calculated based on volume × concentration)

Why endotoxin matters: Endotoxins (bacterial lipopolysaccharides) are present on the outer membrane of gram-negative bacteria. Even trace contamination can trigger an acute phase inflammatory response that confounds in vivo research results — making it appear the compound has inflammatory effects.

Verifying a Janoshik COA#

Janoshik Analytical (Prague, CZ) is the most commonly used independent testing laboratory for EU research compounds. Their COAs include a QR code that links to an online verification page.

How to verify:

1. Scan the QR code on the COA with your phone
2. The Janoshik website opens showing the verified test result
3. Compare: the result on the website should match the COA document
4. Check: the batch number on the website must match the batch number on the vial

If the QR code doesn't work or the batch number doesn't match: Do not use the compound in research — the COA may be fabricated.

Research Use Only. JuicedPharma does not provide medical advice.

Published by JuicedPharma Research Team · October 2026 · Category: Research Protocols & Science