Schoelkopf's acid

Schoelkopf's acid

[′shəl‚kȯpfs ‚as·əd] (organic chemistry) A dye of the following types: 1-naphthol-4,8-disulfonic acid, 1-naphthylamine-4,8-disulfonic acid, and 1-naphthylamine-8-sulfonic acid; may be toxic.