Identification of the triol products of enzymatic hydrolysis of epoxyalcohols 1 and 2. Triol isomers were separated on LC-MS by SP-HPLC of the 1,2-acetonide PFB ester derivative and detected as the M – PFB ion at m/z 369 (7). The top chromatogram illustrates separation of eight triol isomers (A). B–E: Show that human sEH, human EH3, and two constructs of mouse EH3 each hydrolyze epoxyalcohol 1 exclusively to triol 3. F, G: Show that human sEH and human EH3 hydrolyze epoxyalcohol 2 exclusively to triol 1. The HPLC analysis used a Phenomenex HILIC column (100 × 2 mm) with a solvent system of hexane/IPA (100:1, v/v) at a flow rate of 0.4 ml/min.