What is the color development of the Hardness Method 8374?

Document ID

Document ID TE5794

Published Date

Published Date 25/01/2018
Question
What is the color development of the Hardness Method 8374?
Summary
Photos of the color development of Hardness Method 8374
Answer
The following pictures were taken by testing two solutions with Method 8374 for Hardness and the Chlorophosphonazo Indicator Solution Pillows reagent option.
The left-most two cells were filled with 18 MΩ deionized water
The right-most two cells were filled with solution of 500 ppb Calcium as CaCO3.


After Step 5, which is a result of one Chlorophosphonazo Solution Pillow added to each sample cell containing 25 mL of sample and swirled to mix:


After Step 10, which is a result of 1 drop of CDTA Reagent added to the second and fourth sample cells (from the left) and swirled to mix. The first and third sample cells represent the second and fourth cells before adding CDTA and are shown for comparison: