COA, SDS/MSDS and TDS: Essential Documents for Chemical Importers
In international chemical trade, three document types come up in almost every transaction: the certificate of analysis (COA), the safety data sheet (SDS, historically called MSDS) and the technical data sheet (TDS). They answer different questions, they are produced by different people, and confusing them is one of the most common sources of friction between buyers and suppliers. This article explains what each document does, what to check in it, and when to ask for samples — before you commit to an order.
What Each Document Means
COA — Certificate of Analysis
The COA reports the measured results for a specific production lot against the agreed specification: assay, impurities, 수분 함량, appearance and other agreed parameters. It is lot-specific — a COA from last year's batch tells you about last year's batch, not about the lot you will receive.
SDS / MSDS — Safety Data Sheet
The SDS describes hazards, safe handling, 저장, transport classification and emergency measures. It is a regulatory document: many jurisdictions require an SDS in a specific format and language (예를 들어, GHS-aligned formats), and customs brokers, freight forwarders and warehouse operators will ask for it. "MSDS" is the older name for the same document.
TDS — Technical Data Sheet
The TDS describes what the product is designed to do: typical properties, recommended applications, processing guidance. Unlike a COA, the values are typical rather than lot-specific, and unlike an SDS, it is a commercial-technical document rather than a regulatory one.
Why Buyers Should Not Rely on Price Alone
Two offers for "the same" chemical at different prices are often not the same product: they can differ in specification, 불순물 프로필, 포장, documentation completeness and regulatory readiness. A low price with an incomplete document set can become expensive at customs, in the warehouse, or in your production line. Requesting the document set early is the cheapest quality check available — it costs the supplier little if the product is genuine, and it reveals a great deal if it is not. Our guide on sourcing controlled chemicals from China responsibly shows how far documentation-first thinking can carry a buyer in more regulated categories.
How Documents Differ by Product, Supplier and Order Stage
Not every document exists for every product at every moment. A commodity solvent from a large producer usually has a mature SDS and standard specification; a custom intermediate may have a specification negotiated per order and an SDS prepared on request. Documentation availability also depends on order stage: some documents (like the lot COA) can only exist after production. What matters is agreeing up front which documents will be provided, in which format and language, and at which stage — depending on product type, 공급자, order stage and destination requirements.
What to Check in a COA
When you receive a COA, check that: the product name, CAS number and lot number match the goods and the packing list; every parameter in your agreed specification actually appears, with results and limits; test methods are stated where relevant; the results are plausibly lot-specific (identical values across many lots can be a warning sign); and the issue date and signature or stamp are present. If your application depends on a parameter the COA does not report, raise it before shipment, not after arrival.
When to Request Sample Documents
Before the first order with a new supplier, it is reasonable to request a sample COA from a recent lot, the current SDS, and the TDS where applicable. Reviewing these takes minutes and answers three questions at once: does the supplier control this product technically, are they prepared for your destination's requirements, and does their paperwork match their claims? For regulated or higher-risk products, this review is also the natural moment to discuss end-use statements and import requirements on your side — see also what buyers should prepare for acetic anhydride export from China as a worked example.
Buyer Checklist
- Agree the specification in writing before ordering — the COA is only meaningful against an agreed spec.
- Request a sample COA, current SDS and TDS (해당되는 경우) before the first order.
- Confirm SDS format and language requirements for your destination.
- Verify lot numbers match across COA, packing list and labels at receipt.
- Check that all spec parameters appear on the COA with stated test methods.
- Clarify which documents are available at which order stage — some are lot-dependent.
- Keep document sets on file; they are your reference in any later quality discussion.
How SUNCHEM Can Support Your Documentation Review
SUNCHEM coordinates documentation discussion between international buyers and qualified Chinese producers — comparing specifications, collecting sample COAs and SDS, and clarifying what is realistic for a given product and destination. Document availability varies by product type, 공급자, order stage and destination requirements, and we are glad to help you establish what a complete set should look like for your case. Feel free to 저희에게 연락하십시오 with the product and destination you have in mind.