DMA 40% Reports: Understanding “Not Detected” Results
2026-11-12
China Amines Co., Limited
A quality report for dimethylamine 40% aqueous solution lists an impurity as “ND.” Another supplier reports the same component as “<10 ppm.”
Before comparing the materials, establish what each laboratory means. These expressions describe results within a measurement and reporting system; their meaning depends on the method and its limits.
Ask what “ND” means
“ND” commonly means “not detected,” but the report should explain the laboratory’s convention and applicable threshold.
Detection and quantification address different capabilities. A method may detect a component at a level where reliable quantitative reporting remains limited. Eurachem’s method-validation guide discusses these distinctions and their role in analytical reporting.
Ask for the definition used for the particular analyte and sample.
Distinguish detection, quantification, and reporting limits
The limit of detection (LOD) concerns the method’s ability to detect an analyte. The limit of quantification (LOQ) concerns measurement at a level with acceptable analytical performance.
A laboratory’s reporting limit follows its stated reporting policy. Clarify how that threshold relates to the method’s validated capabilities.
Record the threshold, units, and concentration basis alongside the reported result.
Compare the threshold with your requirement
Consider a hypothetical impurity requirement of 20 ppm maximum by mass in the supplied solution.
A report stating “<50 ppm” leaves a gap: that reporting threshold is above the acceptance limit. Request suitable analytical evidence before making a compliance decision.
A result of “<10 ppm” provides more useful information for that requirement, subject to the agreed method and acceptance procedure.
These example values illustrate report interpretation and are not a proposed DMA specification.
Keep each impurity linked to its method
DMA concentration and individual impurity limits are separate quality parameters. Eastman’s DMA 40% specification, for example, lists ammonia and other methylamines individually and identifies gas chromatography as their test method.
For your supply, agree on the required components, limits, methods, and reporting thresholds before ordering.
Discuss your DMA 40% reporting requirements
Send China Amines Co., Limited your approved specification, impurity limits, analytical reporting requirements, quantity, packaging preference, and destination.
Clear reporting requirements help both teams assess the proposed documentation consistently.
Inquiries: info@chinaamines.com