Chelating Agents: Active Ingredient Content of Polyaminopolycarboxylic Acids and Their Salts; Copper PAN Method

摘要

This test method is an alternate to AATCC Method 149, Chelating Agents: Chelation Value of Aminopolycarboxy- lic Acids and Their Salts; Calcium Oxalate Method. The active ingredient content of ethylenediaminetetraacetic acid (EDTA), N-hydroxyethylethylenediaminetriacetic acid (HEDTA) and diethylenetriamine- pentaacetic acid (DTPA) and their salts is usually expressed by the calcium chelation value (CaCV). Titration with a calcium salt using either oxalate or a dye indicator, as done in AATCC Method 149, yields a value which includes partially substituted EDTA, HEDTA, DTPA, ni-trilotriacetic acid (NTA), iminodiacetic acid (IDA), glycolate and other weak chelating agents found in some commercial products. This alternative procedure excludes the effect of the partially substituted products, providing a more stringent value.