Reagent A. Dissolve 0.5 g α-naphthylamine (a carcinogen) in 100 ml 5 N acetic acid by gently heating. Prepare 5 N acetic acid by adding distilled water to 28.7 ml glacial acetic acid (17.4 N) to give final volume of 100 ml.
Reagent B. Dissolve 0.8 g sulfanilic acid in 100 ml 5 N acetic acid by gently heating.
Reagent C. Dissolve 1 g α-naphthol in 200 ml acetic acid.
Cadmium reagent. Place zinc rods in 20% solution of cadmium sulfate for several hours. Draw off precipitated cadmium and add to 1 N HCl.
Original Source: Bacteriological Analytical Manual, 8th Edition, Revision A, 1998.