Question

1.What general compounds in water can interfere with the DPD test? Give three specific examples and procedures to overcome the interferences.

Answer 1

DPD test for chlorine:
Full form of DPD is diethyl-p-phenylene diamine.In this method
powder, DPD react with residual chlorine present in water sample then color of water become pink .If intensity of pink color is more it shows more chlorine present in water sample.

General compound which can interfere DPD test
1.cyanuric acid:
Prevention:
Adjust water pH from 7.4 to 7.6
2.Hardness:
Prevention:
Remove hardness after calcium hardness titration
3.metal:
Metal like Fe and Cu can interfere,remove them by chelating agents.

Thanks: