Abstract
The surface chemistry of aquatic organisms is decisive for their biotic interactions. Metabolites in the spatially limited laminar boundary layer mediate processes, such as fouling, allelopathy, and chemical defense against herbivores. However, very few methods are available for the investigation of such surface metabolites. Here, we give a detailed protocol in which surfaces are extracted by means of C18 solid-phase material, elution of the solid-phase extraction (SPE) material with solvent, and analysis through liquid chromatography–mass spectrometry (LC–MS) and/or gas chromatography–mass spectrometry (GC–MS). The protocol introduced here is based on a previous publication (Cirri et al. 2016) where validation is described. The method is robust, picks up metabolites of a broad polarity range, and is easy to handle. It was developed for the macroalgae Fucus vesiculosus, Caulerpa taxifolia, and Gracilaria vermiculophylla, but can be easily transferred to other algae and to other aquatic organisms, in general.
