Lipid analysis
PEx
PEx samples were extracted from the PTFE membrane using [methanol:dichloromethane:40 mM ammonium acetate(aq)] in the ratios [6:3:2], which was also used as diluent for lipids extracted from BAL and ISP. The latter were extracted using Bligh and Dyer two-phased extraction. The organic phase with lipids was recovered, evaporated under nitrogen, then solubilized in 100 µl of methanol and finally diluted to the optimal assay concentration before analysis by reverse-phase liquid chromatography – mass spectrometry (LC–MS). For further details please refer to the online supplement.