idrogeo

Hi everyone hope you all safe and healthy, I followed the procedure of Kolthoff and Carr "Introduce a measured volume of the persulfate solution containing from 5 to 500 mg. of potassium persulfate into a 125-ml. iodine flask, add water (sufficient to bring the volume to 30 ml.) and 4 grams of potassium iodide. Stopper the flask until all iodide is dissolved and allow it to stand for 15 minutes. Acidify with 1 to 2 ml. of 6 N acetic acid and titrate the iodine with 0.01 or 0.1 N thiosulfate. Apply an indicator correction if necessary." I started preliminary tests prior to my experiments and try to understand in which concentrations of persulfate vary between are convenient and try to reduce the amount of KI that works Can someone explain me a bit in detailed how will I calculate the persulfate amount in mg/L ? Thank you in advance