Two-dimensional ultra high pressure liquid chromatography quadrupole/time-of-flight mass spectrometry for semi-targeted natural compounds identification

•The study reports the identification of 7 new crambescin alkaloids.•It describes a protocol for separation of minor natural products using 2D LC.•The identification is performed using high resolution mass spectrometry and NMR. Isolation of minor compounds from natural extracts remains a complicated task and development of new protocols to facilitate the access to new structure is still needed. Application of a highly efficient 2D LC hyphenated to high resolution mass spectroscopy on the crude extract of the Mediterranean marine sponge Crambe crambe led to the identification of seven new compounds. The structure elucidation has been performed using 2D LC–MS/MS and NMR. The structure elucidation of these minor metabolites encouraged us to speculate on the metabolic pathway leading to this important family of sponge alkaloids.