The nonmutagenicity of purified 4-amino-2-nitrophenol in Salmonella typhimurium.

Two samples of 4-amino-2-nitrophenol were tested for mutagenicity in Salmonella typhimurium strains TA1535, TA1537, TA1538, TA98, and TA100. Significant mutagenic activity was detected with a sample of this compound obtained from Aldrich (technical grade (Aldrich), TGA) both in the presence and in the absence of a rat-liver S9 metabolic activation mixture. When toluene-insoluble contaminants of the TGA product were separated and tested for mutagenicity, they were found to be mutagenic in the same strains as the TGA sample. After removal of these major contaminants from the TGA product its mutagenicity was reduced; a nonmutagenic sample was obtained by further purification. The other sample of 4-amino-2-nitrophenol, which was synthesized and purified in our laboratory, was nonmutagenic. H.p.l.c. profiles of the unpurified TGA sample and the purified samples revealed a large number of contaminants in the TGA product. Likewise, t.l.c. revealed the presence of contaminants in the TGA product.