Why does Hach Sulfide 2 reagent contain potassium dichromate when it is not included in the Standard Method 4500-S2 E or F?

Document ID

Document ID TE1606

Version

Version 2.0

Status

Status Published

Published Date

Published Date 27/05/2017
Question
Why does Hach Sulfide 2 reagent contain potassium dichromate when it is not included in the Standard Method 4500-S2 E or F?
Summary
Sulfide 2 reagent composition
Answer
The Standard Method uses ferric ion as the oxidant, whereas potassium dichromate as a replacement in Hach Sulfide 2 reagent improves the blank color.