What could be the cause of a black color developing during the FerroVer®or TPTZ methods?

Document ID

Document ID TE322

Version

Version 2.0

Status

Status Published

Published Date

Published Date 27/05/2017
Question
What could be the cause of a black color developing during the FerroVer®or TPTZ methods?
Summary
Black color develops during FerroVer®or TPTZ method
Answer
The black color could be produced by a molybdate interference.