Sum of volatile matter (at 135 °C) and chlorides and sulfates (calculated as sodium salts), not more than 13 percent.
Water-insoluble matter, not more than 0.2 percent.
2-Naphthol, not more than 0.4 percent.
Sulfanilic acid, sodium salt, not more than 0.2 percent.
Subsidiary colors, not more than 3 percent.
4,4'-(Diazoamino)-dibenzenesulfonic acid, not more than 0.1 percent.
Lead (as Pb), not more than 20 parts per million.
Arsenic (as As), not more than 3 parts per million.
Mercury (as Hg), not more than 1 part per million.
Total color, not less than 87 percent.
21 C.F.R. §74.1254