DMA 40% Quality: Assay and Impurity Limits Explained
2026-11-12
China Amines Co., Limited
Two batches of dimethylamine 40% aqueous solution can report similar DMA concentrations while having different impurity profiles.
For purchasing teams, the assay establishes one part of the quality picture. Application requirements may also call for limits on individual components and other measurable properties.
Separate concentration from impurity requirements
The DMA assay describes the reported dimethylamine content on the stated analytical basis. Individual impurity results provide additional information about named components.
Eastman’s published DMA 40% sales specification illustrates this structure: it lists a DMA assay range alongside separate limits for ammonia, monomethylamine, trimethylamine, and color. These requirements apply to that manufacturer’s named grade.
Use the specification agreed for your proposed supply when evaluating a quotation or shipment.
Check the method beside each result
Different quality parameters may use different analytical methods.
In the Eastman specification, DMA content is measured by titration, the listed amine impurities and ammonia by gas chromatography, and color by a colorimeter.
This is why a purchasing specification should identify the method alongside each requirement. Ask the technical team to confirm that the proposed testing provides the information needed for your application.
Keep the reporting basis consistent
Check whether impurity limits apply to the supplied solution or another stated basis.
Units also matter. On the same mass basis, 0.040% equals 400 ppm by mass. That conversion is useful only when the compared results describe the same component and use compatible reporting conventions.
For results reported as “less than” a value, clarify the reporting threshold before assessing compliance with a tighter limit.
Define quality through the intended application
Share the quality parameters that matter to your process during supplier evaluation.
Agree on acceptance limits, methods, and batch documentation before placing the order. If a required parameter is absent from a standard COA, discuss how it will be verified and reported.
Retain those agreements with the approved specification so repeat purchases follow the same requirements.
Request a DMA 40% specification review
Send China Amines Co., Limited your application, required assay range, impurity limits, quantity, packaging preference, and destination.
These details help establish a clear basis for reviewing the proposed grade and supporting documentation.
Inquiries: info@chinaamines.com