21 C.F.R. § 74.1602
(a) Identity.
(b) Specifications. D&C Violet No. 2 shall conform to the following specifications and shall be free from impurities, other than those named, to the extent that such other impurities can be avoided by good manufacturing practice:
Volatile matter (at 135 °C.), not more than 2.0 percent. Matter insoluble in both carbon tetrachloride and water, not more than 0.5 percent. p- Toluidine, not more than 0.2 percent. 1-Hydroxy-9,10-anthracenedione, not more than 0.5 percent. 1,4-Dihydroxy-9,10-anthracenedione, not more than 0.5 percent. Subsidiary colors, not more than 1.0 percent. Lead (as Pb), not more than 20 parts per million. Arsenic (as As), not more than 3 parts per million. Total color, not less than 96.0 percent.
[42 FR 15654, Mar. 22, 1977, as amended at 45 FR 62978, Sept. 23, 1980; 55 FR 18868, May 7, 1990]