US EPA

4287303 

Journal Article 

Photochemical Decomposition Of The Dichlorobenzidine-Based Tattoo Pigment Orange 13 In Simulated Solar Light 

Howard, PC; Gopee, NV; Cui, Y; Evans, FE; Couch, LH; Churchwell, MI; Doerge, DR 

2004 

1 

Toxicologist
ISSN: 0731-9193 

TOX/4001875 

78 

1-S 

English 

The art of tattooing has experienced a renaissance over the past several decades, with an increase in popularity especially amoung youth, and migrating from the use of inorganic metals (e.g. HgS) as the color agent to organic pigments. Many of the yellow, orange or red pigments used in tattoo inks are derivatives of 3, 3?- dichlorobenzidine. We used Pigment Orange 13 (PO13; CI 21110), a bisazo pigment of 3, 3?-dichlorobenzidine and 3-methyl-1-phenyl-2-pyrolozin-5-one (MPPone), as a model bisazo pigment for examining photochemical stability of this class of compounds. PO13 was dissolved in tetrahydrofuran, deoxygenated using argon, and exposed in 2 mm cuvettes to simulated solar light using a 6.5 kW xenon arc solar simulator, with irradiance equivalent to terrestrial summer sunlight. The PO13 solution decolorized indicating photochemical decomposition. The products were analyzed by HPLC and isolated using a combination of column and thin layer silica chromatography and HPLC, and analyzed using NMR and mass spectroscopic (MS) methods. The initial photochemical reduction of PO13 involves cleavage at one of the hydrazone groups to yield the mono-MPPone derivative of 3, 3?- dichlorobenzidine and the mono-MPPone derivative of 3, 3?-dichloro-4-aminobiphenyl. 3, 3?-Dichlorobenzidine and 3, 3?-dichloro-4- aminobiphenyl were also identified, presumably through sequential photochemical reduction. The identification of other photochemical products is in progress to elucidate further the pathways for photodecomposition of this pigment. These data demonstrate that photochemical decomposition of a representative 3, 3?- dichlorobenzidine-based tattoo pigment using simulated solar light in an aprotic solvent results in the release of potentially carcinogenic 3, 3?-dichlorobenzidine and 3, 3?-dichloro-4-aminobiphenyl.