What causes a blue color (instead of yellow) to develop on Method 10020 using NitraVer® reagent on DI water and samples?

Document ID

Document ID TE527

Version

Version 2.0

Status

Status Published

Published Date

Published Date 27/05/2017
Question
What causes a blue color (instead of yellow) to develop on Method 10020 using NitraVer® reagent on DI water and samples?
Summary
Blue color develops on Method 10020 using NitraVer® reagent
Answer
The purple/blue color is most likely a result of formaldehyde or organic aldehyde contamination. This contamination is most likely from the sulfuric acid used in the test. Try a different sulfuric acid source and make sure all pipets/tips are clean.