Certificate of Analysis (CoA) vs SDS vs TDS: What Each Document Is For

Buyers of chemicals often ask for three documents: the Certificate of Analysis, the Safety Data Sheet and the Technical Data Sheet. They answer different questions and are not interchangeable.

Certificate of Analysis (CoA)

A CoA reports the test results for a specific batch or lot against the product specification. It typically lists the product name, batch number, manufacturing and test dates, each tested parameter with its specification limit and measured result, the test method, and an authorised signature. It answers the question "does this batch meet the specification?"

Safety Data Sheet (SDS)

An SDS describes the hazards of a product and how to handle, store, transport and dispose of it safely. It applies to the product in general rather than to one batch, and it is legally required for hazardous chemicals in most markets. It answers "how do I handle this safely?" See the 16 sections of an SDS.

Technical Data Sheet (TDS)

A TDS describes the product's typical properties, intended uses, performance and recommended application or dosage. It is a marketing and technical document rather than a regulatory one. It answers "what is this product and how do I use it well?"

Side by side

• Scope: the CoA covers one batch, while the SDS and TDS cover the product.
• Purpose: the CoA proves conformity, the SDS communicates hazards, the TDS describes use and performance.
• Legal status: the SDS is legally required for hazardous chemicals. The CoA and TDS are usually contractual or commercial.
• Update trigger: a new CoA is issued for every batch. An SDS or TDS is updated when the product, hazards or regulations change.

Does a CoA need to follow a standard format?

There is no single legal template. Customers or industry standards often specify required parameters and methods, so agree the content with each buyer. A good CoA is traceable to the batch, lists methods, and is signed by an authorised person.

If you manage all three documents, keep the product name, composition and batch references consistent across them. Inconsistencies are a common reason for customer queries. For writing an SDS, see how to write a Safety Data Sheet.