A　porphyrin/peroxynitrite　biomimetic　system　was　used　to　study　the　metabolism　of　indeno[1,2,3-cd]pyrene　(IND)　induced　by　peroxynitrite.　The　metabolites　were　identified　using　high-performance　liquid　chromatography　coupled　with　electro-spray　ionization　tandem　mass　spectrometry　as　OH-IND,　IND-quinone　and　2NO(2)-IND.　By　stopping　the　reaction　at　different　stages,　we　discovered　that　IND　was　first　transformed　to　IND-quinone　and　2NO(2)-IND,　which　were　then　transformed　to　OH-IND.　Mutation　assays　including　Ames　tests　and　cell　transformation　experiments　showed　enhancement　of　the　mutagenicity　after　the　activation　by　the　peroxynitrite/Fe(III)porphyrin　system.　The　results　also　showed　that　2NO(2)-IND　and　IND-quinone　played　key　roles　in　the　mutagenicity　of　PAHs　after　metabolic　activation.