Identification and Quantification, by NMR and LC-MS, of Sterols Isolated from the Marine Sponge Aplysina aerophob Pere Ferriol, Francisco J. Toledo Marante, Ignacio Brouard Martin, José J. Santana Rodríguez, Rayco Guedes Alonso, Alba González Benkovics and Roberto Mioso

Aplysterol, several didehydroaplysterols, and their acetylated derivatives were isolated from samples of the marine sponge Aplysina aerophoba, which had been collected on the coast of the Canary Islands, and were identified by chromatography and 1H- and 13C-NMR spectroscopy. A quantitative analysis was done, based on the relative intensities of the signals corresponding to the olefinic quaternary carbons from the 13C-NMR spectrum at 125 MHz. Finally, the results described were confirmed by ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS).