Data for: Preservation protocol for dimethylsulfoniopropionate and dimethylsulfoxide analysis in plant material of the Mediterranean seagrass Posidonia oceanica, and re-evaluation of dimethylsulfoniopropionate leaf content

Dimethylsulfoniopropionate (DMSP) and dimethylsulfoxide (DMSO) leaf content of Posidonia oceanica in samples preserved with three treatments: oven dried at 60°C for 24h, frozen at -20°C, and frozen-in-ice and kept at -20°C. The DMSP content was analyzed by proxy as dimethylsulfide (DMS) by gas chromatography after alkaline cleavage at room-temperature.