How to read a certificate of analysis

A certificate of analysis, often shortened to COA, is a laboratory report on one specific lot of a material. It records what was examined, which methods were used and what the measurements were. It is a record of that lot only, and it says nothing about any other lot.

The identifying details

The top of a certificate says what it describes. Read this part first, because a certificate is only useful if it belongs to the material in front of you.

• The name of the compound, and for a blend, each component.
• The stated amount per vial, such as a strength in milligrams.
• The lot or batch number.
• The name of the laboratory that carried out the analysis.
• The date of the analysis or of the report.

Identity

An identity result answers one question: is this the compound the label names? For peptides the usual method is mass spectrometry, which measures the mass of the molecules in the sample.

The certificate normally shows the expected mass, calculated from the sequence, beside the mass that was observed. The two should agree within the tolerance of the instrument.

Purity

Purity is most often measured by high-performance liquid chromatography, or HPLC. The instrument separates the sample into its components and draws each one as a peak. The figure reported is the area of the main peak as a share of the area of all peaks detected.

A purity figure describes what the detector could see. It is not a statement of how many milligrams are in the vial, which is a separate measurement.

Quantity

Some certificates also report how much of the compound was found, by weight. Where it appears, compare it with the amount stated on the label.

Matching a certificate to a vial

Check the compound name, the stated amount and the lot number against the vial label. All three should match. A certificate for one size of a product does not describe a different size, even when the compound is the same.

When a certificate is published for a Luminex Research product, it is listed in the COA library under that product, that size and that lot.

What a certificate does not tell you

A certificate reports analytical measurements. It does not say that a material is suitable for any particular purpose. Luminex Research products are sold for laboratory research use only and are not for human consumption.