A spectrophotometric assay for the detection of 2-aminophenols in biological samples.

A sensitive and efficient spectrophotometric assay is described for the determination of 2-aminophenols in biological samples. Using ferric ions as a metal catalyst, 2-aminophenol dimerizes in an acidic aqueous environment to 2-hydroxyisophenoxazin-3-one, an intensively colored dye. The newly developed assay is suitable for the detection of 2-aminophenols in the micromolar range. The paper demonstrates that this chemical assay is also applicable for the determination of 2-aminophenols substituted with a halogen at the ortho, meta, or para position of the aromatic ring with respect to the amino moiety, lambda max, and the molar extinction coefficient varying with the substituent pattern. Results obtained for fluorinated 2-aminophenol detection in biological samples by either this new method or 19F NMR are similar. This observation corroborates that the newly developed assay is suitable for detection of 2-aminophenols in biological samples.