What are known interferences on the 5500AMC method?

Document ID

Document ID TE2742

Published Date

Published Date 27/05/2017
Question
What are known interferences on the 5500AMC method?
Summary
Interferences on the 5500AMC method
Answer
The known interferences to the AMC/APA phenate method are high alkalinity and hardness, which can cause precipitation of dissolved salts at the conditions of the reaction in the AMC/APA due to very high pH.  If sample alkalinity is very high (greater than 800 mg/L as CaCO 3) and comprised by bicarbonate/carbonate, the readings may appear lower than they are.  Such situations are rare and do not normally occur in drinking water applications, however, may be present in water reuse applications, when mineralization is high.