FIGURE 5.

LC-MS/MS detection of O-8-monomethylated B[a]P-7,8-catechol in the extracted samples from A549 (A), H358 (B), and HBEC-KT (C) cells at 24 h. B[a]P-7,8-dione (2 μm, 0.2% DMSO) in HBSS buffer were incubated with lung cells and collected at 0 and 24 h, respectively. The culture media were extracted with ethyl acetate. The organic phases were dried under vacuum and redissolved in methanol. O-Methylated B[a]P-7,8-catechol was analyzed with LC-MS/MS by monitoring reaction transition m/z 299→239 ([M + H]⁺ → [M + H − 32 − 28]⁺). The peak had the same retention time and mass transition as authentic O-8-monomethylated B[a]P-7,8-cactechol.