Liquid Chromatography Chromatograms and mass spectra from the acylation reactions of lactucin, lactucopicrin and dihydrolactucopicrin with vinyl acetate, as well as the acylation of DHLc with vinyl chloroacetate, propionate, hexanoate and octanoate were obtained on the following system : LC-MS Waters ACQUITY UPLC I-Class system equipped with a UPLC I BIN SOL MGR solvent manager, a UPLC I SMP MGR-FTN sample manager, an ACQUITY UPLC I-Class eK PDA Detector photodiode array detector (210-400 nm) and an ACQUITY QDa (Performance) as mass detector (full scan ESI+/-in the range 30-1250). Acquity BEH C18 column (1.7 μm particle size, dimensions 50 mm × 2.1 mm) was used for UPLC analysis. The injection volume was 0.5 μL. For a 5 min analysis, the elution was done at pH 3.8 from 100 % H2O/0.1 % ammonium formate to 2 % H2O/98 % CH3CN/0.1 % ammonium formate over 3.5 min. A flow rate at 600 µL/min was used. For a 30 min analysis, the elution was performed at pH 3.8 from 100 % H2O/0.1 % ammonium formate to 100 % CH3CN/0.1 % ammonium formate over 25 min. A flow rate of 600 µL/min was used.