Published 2026-06-24 · Updated 2026-08-26 · Prepared and reviewed by the Demeto Technical & Quality Team. Final acceptance must follow the agreed test methods, commercial-lot evidence and written technical agreement.
Start with identity and lot linkage
Confirm the product name, CAS number, grade, lot number, production date and document issue date. The shipment and the COA should refer to the same lot.
Separate specification from typical data
A COA reports batch results. A TDS usually presents typical properties. Only written specifications and transaction documents define the agreed acceptance limits.
Review the critical indicators
For DMT, these commonly include purity, color, acid value, moisture, ash and process-relevant trace impurities. Check units and test methods before comparing suppliers.
Use the SDS for safety decisions
The SDS covers hazards, handling, storage, exposure controls, transport and emergency response. It should not be used as a substitute for batch quality data.
Create a release checklist
Record document revision, batch identity, results versus limits, deviations and approval status. A repeatable checklist makes supplier and batch comparison more reliable.
Compare like with like
Two certificates are not directly comparable when units, sampling conditions, detection limits or analytical methods differ. Resolve those differences before deciding that one value is better or worse. For a sensitive application, ask both suppliers to report against the same agreed method or arrange a controlled third-party retest.
Treat representative files as pre-qualification evidence
A representative COA can show the supplier's normal reporting structure, but it does not release the commercial lot. Before shipment, confirm the actual lot number, agreed specification, packaging identity and shipment-specific COA. Keep the approved file with the purchase record and retained-sample reference.
Plan the exception path before an exception occurs
The transaction documents should state who samples, which retained sample controls, how a retest is conducted, when a mutually accepted laboratory is used and what remedies apply. Defining this path in advance prevents a technical disagreement from becoming an unstructured commercial dispute.
Sources and use boundary
- OSHA Appendix D — Safety Data Sheet content
- ECHA — Dimethyl terephthalate substance information
- PubChem — Dimethyl terephthalate, CID 8441
This article combines public references with a procurement and qualification framework. It does not replace the current SDS from the actual source, the written product specification, agreed test methods or evidence for the commercial lot.