The extraction of lipids and of lipid oxidation products was performed by adding 1 mL hexane-isopropanol (3:2 v/v) to ~ 1.5 mL emulsion and vortexing thoroughly, as described previously. The mixture was centrifuged at 4,000xg for 20 min, and the upper layer, containing hexane and extracted lipids, was carefully separated from the bottom layer. Hexane was evaporated under a stream of nitrogen at 25 °C until constant weight, and the remaining oil was treated with a nitrogen blanket and frozen at -80 °C for at least 48 hrs until further measurements were performed.