400
I want to know where Mr. Brown was poisoned. I can identify the types of foods he ate by testing the macromolecular composition with Iodine, Biuret and Benedict's Solution.
If I test Mr. Brown's stomach contents for Iodine, Biuret and Benedict's and I measure the color changes for each test then I will find that he tested positive for Iodine and Biuret, because he ate at Ruth's Chris and ordered steak and potatoes.