For the Potassium Iodide 10% solution listed in the Part 3 Reagents guide, it says "(For determination of free chlorine.) Dissolve 1 g of potassium iodide in water, and dilute with water to 10 mL. Prepare the solution at the time of use."
When using this solution while testing for Peroxides of THF per ACS monograph, does that "Prepare the solution at the time of use" still apply?
Also, what does the (For determination of free chlorine) portion mean?