Research Compound COA Checklist
A Certificate of Analysis is the documentary record that links a specific batch of research compound to the analytical data confirming its identity, purity, and physical characteristics.
Why the COA Is Your First Line of Quality Defense
A Certificate of Analysis is the documentary record that links a specific batch of research compound to the analytical data confirming its identity, purity, and physical characteristics. Without a COA — or with a fraudulent or incomplete one — a researcher has no objective basis for knowing what is actually in their vial. This is not a bureaucratic formality. Impure, misidentified, or degraded compounds produce confounded results, waste research resources, and in in vivo contexts introduce variables that can invalidate entire experimental series.
The checklist below is structured in order of evaluation priority. Items marked Required are non-negotiable for research-grade material. Items marked Recommended represent best practice. Items marked Optional are context-dependent but add meaningful quality assurance in specific research settings.
Compound Identification
Verify the COA states the full chemical name, sequence (for peptides), molecular formula, and exact molecular weight. Confirm these match the product you ordered — including salt form (e.g., acetate vs trifluoroacetate), since salt content affects net peptide mass per vial.
Lot and Batch Traceability
The COA must list a unique lot or batch number that matches the label on your physical vial. This is the link between the analytical data and the specific material in your hand. A COA without a matching lot number is a generic template and provides no batch-specific assurance.
Purity Analysis (HPLC)
Look for a measured HPLC purity value (e.g., 99.3%) — not a range or a "≥98%" specification. The COA should state the column, detection wavelength (typically 214 nm for peptide bonds), and mobile phase gradient used. A representative chromatogram should be available on request.
Identity Confirmation (Mass Spectrometry)
Mass spectrometry confirms the compound is the intended molecule, not just a pure unknown. The COA should report the observed mass (e.g., [M+H]⁺) alongside the expected theoretical mass, with a tick or "confirmed" notation when the two agree within instrument tolerance.
Physical Characteristics and Additional Testing
Appearance (white lyophilized powder, etc.), water content (Karl Fischer), residual solvents, and where relevant, endotoxin (LAL method, <0.5 EU/mg for in vivo work) should all be documented. The COA's analysis date should be recent — ideally within 12 months of receipt.
COA Red Flags: When to Reject a Document
The following findings on a COA, or its absence, are grounds to reject the document and request a corrected version or seek an alternative supplier:
A COA without a unique lot number is not linked to your specific vial. It may be a generic template document applied to all shipments regardless of actual test results. Always verify the lot number matches your vial label exactly.
Real analytical results are specific numbers. A stated range or minimum is a specification, not an analytical result. If no actual measured purity percentage from the specific lot is provided, the compound has not been individually tested — or the result is being concealed.
Without MS data, there is no confirmation the compound is the correct peptide. High HPLC purity alone only confirms a highly pure substance is present — not that it is the intended compound. Both HPLC and MS are required together for complete quality verification.
A molecular weight discrepancy beyond instrument tolerance indicates a sequence error (deleted or substituted amino acid), an unexpected modification (oxidation, deamidation, incomplete deprotection), or an incorrectly labelled compound entirely. Do not use the material without resolution from the supplier.
A COA dated significantly before the purchase date may indicate the supplier is using a single historical test document for all lots of a compound rather than testing each production batch. Fresh material should have a recent COA.
A purity figure without a specified method (column, wavelength, gradient) cannot be independently reproduced or critically evaluated. This absence suggests the data may not have been generated by a legitimate analytical laboratory following documented procedures.
Legitimate analytical laboratories retain raw chromatogram data for all tested lots. A supplier who cannot or will not provide the underlying chromatogram upon reasonable request has no verifiable evidence for their stated purity figure.
Quick Reference: Acceptable vs Unacceptable COA Data
COA Field | Acceptable | Unacceptable HPLC Purity | 99.3% (specific measured value) | ≥98% (range only, no measured result) Mass Spec Result | Observed: 712.0 [M+H]⁺ · Expected: 711.9 · ✓ Confirmed | Absent, or "MS: Pass" with no values stated Lot Number | IPA-2026-0312-A (specific, matches vial label) | None, or "N/A" Analysis Date | March 12, 2026 (within 12 months of receipt) | January 15, 2023 (recycled document) HPLC Method | C18 column, 214 nm, ACN/H₂O + 0.1% TFA gradient | "HPLC" with no further detail Endotoxin (in vivo use) | <0.5 EU/mg (LAL method) | Not tested / absent Appearance | White lyophilized powder | Absent from COA Salt Form | Acetate salt (clearly specified) | Not stated
File a copy of the COA alongside your research notes for every compound used in a published protocol. Journals and institutional review processes increasingly require traceability documentation for research materials — having the lot-specific COA on record allows you to demonstrate the quality standard of material used in any experiment, and enables retrospective investigation if questions about compound quality arise after publication.