... 16 ppbMilk/Milk powder (Method two).......................................................... 1 ppbTissue (chicken, pork, duck, fish, ... each2) 6× standard solution (1 mL each): 0 ppb,1 ppb, 3 ppb, 9 ... ppb, 27 ppb, 81 ppb3) Enzyme conjugate (7 mL)............................................................... red cap4) Antibody working solution (7 mL ...