Certificate of Analysis vs. Safety Data Sheet: What Is the Difference?

Certificates of Analysis and Safety Data Sheets are both important laboratory documents, but they serve different purposes.

A Certificate of Analysis, or CoA, generally documents selected characteristics and test results associated with a material or production lot.

A Safety Data Sheet, or SDS, communicates information concerning chemical hazards, protective measures, storage, handling, exposure response, and related safety topics.

One document should not be treated as a replacement for the other.

What is a Certificate of Analysis?

The precise format of a CoA varies between organizations and industries.

FDA has described a Certificate of Analysis as a supplier-provided document that records certain characteristics and attributes of a component, and has explained that supplier CoAs may be relied upon only when supplier reliability is appropriately evaluated and periodically verified.[1] For a peptide research material, a CoA may report information such as:

• Product or material name
• Amino-acid sequence
• Lot or batch number
• Date of manufacture or testing
• Physical appearance
• Molecular formula
• Theoretical molecular mass
• Observed mass-spectrometry result
• Chromatographic purity
• Peptide content or assay
• Water content
• Counterion content
• Residual solvents
• Storage conditions
• Testing laboratory
• Approval or release signature

Not every CoA includes every item, and the presence of a field does not establish that the test was adequately designed or independently performed.

Why the lot number matters

Analytical results should be traceable to the material being evaluated.

A lot-specific CoA connects the reported results to a defined production batch. A generic example certificate, marketing graphic, or certificate from a different lot does not establish the analytical characteristics of the material currently supplied.

Lot traceability is central to meaningful comparison because manufacturing and impurity profiles can vary between batches. FDA guidance for active pharmaceutical ingredients emphasizes batch identity testing, supplier qualification, comparison with specifications, and periodic confirmation of certificate reliability.[2]

What is a Safety Data Sheet?

An SDS is a standardized hazard-communication document.

OSHA's Hazard Communication Standard uses a 16-section format covering chemical identification, hazards, composition, first aid, firefighting, spill response, handling, storage, exposure controls, physical properties, stability, toxicology, transportation, disposal, and other regulatory topics.[3] The sections are:

1. Identification
2. Hazard identification
3. Composition and information on ingredients
4. First-aid measures
5. Firefighting measures
6. Accidental-release measures
7. Handling and storage
8. Exposure controls and personal protection
9. Physical and chemical properties
10. Stability and reactivity
11. Toxicological information
12. Ecological information
13. Disposal considerations
14. Transport information
15. Regulatory information
16. Other information

OSHA requires the specified information in Sections 1 through 11 and Section 16. Sections 12 through 15 appear in the standardized format but are not enforced by OSHA, because those subjects are administered by other agencies.[3]

What does an SDS tell a researcher?

An SDS is designed to help people identify and manage workplace chemical hazards. Researchers may consult it to determine:

• Which protective equipment may be appropriate
• Whether engineering controls are recommended
• What to do after accidental exposure
• How to respond to a spill
• Which materials may be incompatible
• Which environmental conditions should be avoided
• Whether special fire-response procedures apply
• How the supplier classifies the chemical's known hazards
• Whether toxicological information is available or unavailable

OSHA explains that Sections 1 through 8 emphasize identification, hazards, safe handling, and emergency controls, while later sections contain technical information concerning properties, stability, reactivity, toxicology, and document revision.[4]

What an SDS does not normally establish

An SDS is not ordinarily a lot-specific analytical report. It generally does not establish:

• HPLC purity for the supplied lot
• Mass-spectrometric confirmation of the supplied lot
• Exact peptide content
• Sequence confirmation
• Lot homogeneity
• Sterility
• Endotoxin results
• Biological activity
• Stability through a claimed expiration period
• Pharmaceutical approval status

An SDS may list an identifier, composition information, or certain physical properties, but that information is presented for hazard communication rather than comprehensive analytical certification.

What a CoA does not normally establish

A CoA should not be treated as a complete safety document. A chromatogram, mass spectrum, or purity result does not tell laboratory personnel how to respond to a spill, what protective equipment is appropriate, whether incompatible chemicals must be segregated, or which first-aid procedures are recommended.

A CoA also does not automatically prove every unreported characteristic. Chromatographic purity does not independently prove sterility, endotoxin status, identity, total peptide content, or biological activity.

A CoA comparison checklist

When comparing Certificates of Analysis, look beyond the largest percentage printed on the page.

• Confirm the lot number. The certificate should correspond to the label or documentation associated with the material.
• Identify the test method. A result is more informative when the method and analytical principle are identified.
• Separate purity from identity. HPLC and mass spectrometry answer different questions, as covered in our article on peptide purity and identity.
• Look for the actual data. Chromatograms, spectra, integration tables, and system information provide greater context than a pass/fail statement alone.
• Check the testing organization. Determine whether the tests were performed by the supplier, manufacturer, contract laboratory, or another organization.
• Review dates and signatures. Testing date, report date, approval date, and revision history help establish document traceability.
• Determine what was not tested. An omitted result should not be assumed to have passed. "Not reported," "not tested," and "not detected" have different meanings.

What does "third-party tested" mean?

The phrase can describe several different arrangements. A third-party laboratory may have:

• Tested a sample supplied by the seller
• Tested a sample supplied by the manufacturer
• Collected the sample independently
• Tested one production lot
• Tested a different or earlier lot
• Performed only one analytical method
• Issued a full laboratory report
• Supplied only a summarized result

The phrase is therefore most meaningful when the report identifies the lot, sampling source, laboratory, methods, dates, results, and chain of custody.

Should a CoA be accepted without verification?

That depends on the requirements of the laboratory and application.

In regulated manufacturing, FDA guidance allows reliance on supplier certificates under defined circumstances, but it also calls for supplier evaluation, identity testing, periodic complete analysis, and regular checks of CoA reliability.[2] Even outside regulated manufacturing, the underlying principle is useful: documentation is strongest when it is traceable, method-specific, lot-specific, and subject to appropriate verification.

Why both documents matter

The CoA and SDS answer fundamentally different questions.

• The CoA asks: what selected analytical characteristics were reported for this material or lot?
• The SDS asks: what known hazards and protective measures should be considered when handling this chemical?

A laboratory may need both documents, along with internal risk assessments, protocols, specifications, training records, and other technical information.

Key takeaway

A Certificate of Analysis is primarily an analytical and quality document. A Safety Data Sheet is primarily a hazard-communication document.

Neither should be expected to answer every question about a peptide material. Responsible evaluation requires understanding what was tested, what was not tested, which lot the information applies to, and what purpose the document was designed to serve.

References

1. FDA: Small Entity Compliance Guide - CGMP in Manufacturing, Packaging, Labeling, or Holding Operations for Dietary Supplements (2010) - Defines a supplier Certificate of Analysis and the supplier-reliability and periodic-reconfirmation expectations. Cited here for its definition of a CoA; the rule itself applies to dietary supplements under 21 CFR part 111, not to drug manufacturing.
2. FDA/ICH Q7A: Good Manufacturing Practice Guidance for Active Pharmaceutical Ingredients (2001) - Batch identity testing, supplier qualification, and periodic confirmation of certificate reliability.
3. OSHA 1910.1200 Appendix D: Safety Data Sheets (Mandatory) - The 16-section SDS format and the scope of OSHA enforcement.
4. OSHA Brief: Hazard Communication Standard - Safety Data Sheets (DSG BR-3514, 2012).
5. McCarthy D, Han Y, Carrick K, et al. Reference standards to support quality of synthetic peptide therapeutics. Pharm Res 2023;40:1317-1328. PMC10338602.

Related educational articles

• How to Read a Peptide Certificate of Analysis (COA)
• Peptide Purity and Identity: HPLC, Mass Spectrometry, and Certificates of Analysis
• Peptide Salts and Counterions: What Do Acetate, TFA, and Hydrochloride Mean?

This article summarizes publicly available research for educational purposes and does not constitute medical advice, a therapeutic claim, or a recommendation for human use. Products referenced are sold for laboratory research use only.