How to Read a 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 foundational quality document for any research compound purchase. It summarizes the analytical testing results that verify a compound's identity, purity, and compliance with specifications. Being able to correctly read and critically evaluate a COA is an essential skill for any researcher procuring compounds for laboratory use — it's the difference between trusting a document and understanding it.

COA Document Structure#

A properly structured COA contains these sections:

Header:

• Laboratory name, address, accreditation numbers (ISO, GLP)
• Report ID / analysis number (key for verification)
• Date of analysis
• Client/supplier name (optional: some labs keep this confidential)

Sample Information:

• Compound name and CAS number
• Batch/lot number
• Physical description (white powder, off-white lyophilized cake)
• Quantity received

Test Results Table: One row per test performed, typically:

Signatures:

• Analyst signature and date
• Quality assurance/manager sign-off

Reading Purity Results#

Purity (HPLC area%):

• "99.3%" means 99.3% of UV-absorbing material at the measurement wavelength is the target compound
• The remaining 0.7% is other UV-absorbing material (impurities or degradation products)
• This is relative purity — it assumes the target compound and all impurities have similar UV absorbance

Important nuances:

• 99.3% purity by area% ≠ 99.3% by weight/mass — compounds with different molecular weights and UV extinction coefficients contribute different "signal" per gram
• Low-UV-absorbing impurities may be underrepresented in HPLC-UV purity — HPLC-ELSD or weight-corrected calculations give a truer picture
• For research purposes, HPLC-UV ≥98% is the accepted standard for most applications

What to check in purity testing:

• Measurement wavelength (should be 210–220 nm for broadest detection; 214 nm is standard for peptides)
• Column type (C18 reverse-phase for most peptides and steroids)
• Gradient details (verify method is appropriate for the compound class)

Reading Identity Test Results#

Mass spectrometry (MS) confirmation:

ESI-MS for peptides shows multiply charged ions:

• Look for: Observed m/z value AND corresponding charge state
• Example: "Observed [M+2H]2+: 710.8 m/z; Calculated: 710.8 m/z; Match: Yes"
• This proves the compound has MW of approximately 1,419.5 Da (2 × 710.8 − 2 = 1,419.6)

GC-MS for steroids:

• Retention index compared to reference library
• Fragmentation pattern match (typically expressed as % similarity to NIST library reference)
• ≥95% NIST library similarity = confident identification

What if MS is missing?

• COA shows only HPLC-UV purity without MS identity confirmation
• For common well-established compounds (testosterone enanthate) with standardized HPLC methods and known retention times: may be acceptable
• For peptides: HPLC-UV alone is insufficient; MS confirmation should be required because sequence errors cannot be detected by UV

Reading Endotoxin Results#

LAL (Limulus Amebocyte Lysate) test:

• Measures bacterial endotoxins (lipopolysaccharide, LPS) in EU/mg (Endotoxin Units per milligram)
• USP <85> standard: research injectables typically should be <10 EU/mg
• Result of 1.2 EU/mg is well within specification; result of 8.5 EU/mg is passing but near limit

Why endotoxin matters: 0.1 ng/kg LPS in rodents activates the immune response. Endotoxin contamination in research compounds is the single most common source of false-positive inflammatory results in in vivo studies.

Verifying COA Authenticity#

How to verify a Janoshik COA:

1. Note the report ID (alphanumeric code on the COA)
2. Go to janoshik.com
3. Use the "Verify Report" function
4. Enter the report ID
5. The live database should return the matching test results

Red flags for fake COAs:

• No report ID present
• Report ID does not return results on lab website
• Date is more than 2 years old (compound may have degraded; batch is likely outdated)
• Purity exactly 99.9% on every compound, every batch (real testing shows variation)
• Lab name is not a real accredited laboratory

Complete Checklist for COA Evaluation#

Before purchasing:

• Third-party lab (not supplier self-tested)
• Report ID present and verifiable on lab website
• Date within 12–24 months
• Compound name + CAS number match expectation
• Batch/lot number listed
• HPLC purity ≥98% (or ≥95% minimum)
• Identity confirmed (MS for peptides; GC-MS or MS for steroids)
• Endotoxin result if injectable use planned

Research Use Only. JuicedPharma does not provide medical advice.

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