Does Hach have a method for testing specifically monochloramine?

Document ID

Document ID TE184

Published Date

Published Date 25/01/2018
Question
Does Hach have a method for testing specifically monochloramine?
Summary
Method for Monochloramine
Answer
Hach developed Indophenol method numbers 10171(LR) and 10172 (HR) for Chloramine (Mono), which is very specific for monochloramines. The test involves adding a single reagent to the sample, a 5 minute reaction time, and measuring the concentration in a colorimeter or spectrophotometer.

Hach does not recommend using the difference between a total and free DPD chlorine test for measuring monochloramine. This is because high levels of monochloramine interfere with the free DPD chlorine test, causing the reading to continually increase. Therefore an accurate reading for free chlorine in chloramination systems cannot be measured.

In addition to methods 10171/10172 for monochloramine, the Hach method 10200 measures free ammonia as well as monochloramine to help water facilities optimize the feeding ratio of chlorine to ammonia.

You can download copies of all of the methods referenced above at hach.com/WAH.