What could cause a blue or purple color in the Nitrate Chromotropic Acid TNT Method 10020?

Document ID

Document ID TE7155

Published Date

Published Date 25/01/2018
Question
What could cause a blue or purple color in the Nitrate Chromotropic Acid TNT Method 10020?
Summary
Blue or purple color in the Nitrate Method 10020
Answer
In the Nitrate Chromotropic Acid TNT Method 10020  the purple color is most commonly seen with formaldehyde or organic aldehyde contamination. This contamination is common to sulfuric acid but can come from other sources. To resolve this issue change the sulfuric acid source and clean all glassware, plastic containers, and pipets.