EDTA Titration Metal Ion Masking

EDTA titration can use masking agents to keep one metal ion from reacting right away. A masking agent forms a stable complex with a chosen ion, while other metal ions can still react with EDTA. This makes it possible to analyze ions one after another in a mixture.

Several masking agents are used ...

The selectivity of EDTA reactions is improved by masking and demasking agents.

A masking agent chelates with a potential interfering ion to form a more stable complex than the unwanted EDTA complex, keeping the ion from participating in the reaction.

Cyanide, fluoride, triethanolamine, and thiourea are common masking agents.