FIGURE 10.

Quantitative analyses of 9-HODE, epoxyalcohol, and triols in human epidermis. The unlabeled products (endogenous) are in the upper chromatograms and the corresponding d4 internal standards are in the bottom chromatograms. A, LC-MS analysis of 9-HODE as the PFB ester, monitoring m/z 295 (d0) and m/z 299 (d4). B, LC-MS analysis of the main epoxyalcohol as the PFB ester (d0 at m/z 311 and d4 at m/z 315). C, LC-MS analysis of linoleate triols as the PFB ester DMP derivative (d0 at m/z 369 and d4 at m/z 373). The analyses used normal phase LC-MS with a Thomson Advantage silica column (25 × 0.46 cm) and solvents of hexane/IPA in the proportions 100:1.5 (v/v) for 9-HODE and epoxyalcohol analyses and 100:1 (v/v) for the triols with a flow rate in 1 ml/min.