Thanks for the reply. What do you mean by “Both are colorless”? I know the yellow pigment is an impurity but I thought it would be removed by the Cbleach in the boiling flask. I expected detla 8 to be translucent as shown by the photos @Deleted included above. Maybe I misunderstood?
Your correct in saying that besides color change there is no way to tell if the reaction took place or now without analytics or TLC. I will give the bioassay a try.