Fig. 1.

LC-MS analysis of the product formed from E1 on exposure to •OH generated by the Fenton reaction. (a) Extracted ion-current chromatogram (m/z 287); mass spectra are from the major LC peak at t_R = 1.3 min; (b) full-scan APCI-MS; (c) MS/MS (MS²) product-ion scan from the molecular ion m/z 287 isolated as the precursor; and (d)MS³ product-ion scan of m/z 269 (the major product ion of the MS², c). Fragmentation pattern and t_R are identical to those of a synthetic 10β-hydroxyestra-1,4-dien-3,17-dione (E1-quinol).