Abstract
This article presents a structured approach to reviewing a Certificate of Analysis, covering identifier matching, method disclosure, data presentation, and the common gaps that reduce a document's evidential value.
Reviewing a Certificate of Analysis takes a few minutes and is most effective when it follows a consistent sequence. The purpose is not to find fault but to establish how far the document supports conclusions about the specific material received.
Start with the identifiers
Confirm that the compound name and batch identifier on the document match the label on the container exactly. A mismatch, or a document referring to a product line rather than a batch, means the report cannot be tied to the material in hand regardless of how good the underlying data are.
Check the issuing laboratory and date
The report should name the laboratory that performed the analysis, carry that laboratory's own reference number, and state the date of analysis. A recent date matters most for compounds where stability is a known concern.
- Compound name and batch identifier matching the physical label
- Named testing laboratory with its own report reference
- Date of analysis and quantity of sample submitted
- Analytical methods stated, not merely implied
- Chromatograms and spectra included rather than summarised
- A means of verifying the report independently of the supplier
Look for methods, not just results
A purity figure is interpretable only alongside the method that produced it. Column, gradient, and detection wavelength determine which related substances are separated and how strongly they respond. Where these details are absent, the number should be treated as indicative rather than comparable.
A number without a method is a summary. A number with a method is a measurement.
Read the raw data where provided
Appended chromatograms and mass spectra allow independent assessment. In a chromatogram, look for a symmetric main peak, a stable baseline, and clear resolution from adjacent peaks. In a mass spectrum, check that the observed mass agrees with the theoretical mass for the stated sequence within the expected tolerance.
Common gaps
The most frequent shortcomings are documents without a batch identifier, purity figures without disclosed methods, reports that cannot be verified at source, and summary tables presented without the underlying data. None of these necessarily indicate a problem with the material, but each limits what the document can be used to demonstrate — and that limit should be recorded in the research file alongside the report itself.
