Water samples were either acidified to pH 2 or processed without acidification (pH 8) prior solid-phase extraction (SPE). SPE was performed in quadruplicates. Thus, the given concentrations and elemental ratios of solid-phase extracts are average values of quadruplicate measurements (+/- standard deviation).Some values for SPE-V and SPE-As were below limit of detection (LOD).

Supplement to: Ksionzek, Kerstin B; Zhang, Jing; Ludwichowski, Kai-Uwe; Wilhelms-Dick, Dorothee; Trimborn, Scarlett; Jendrossek, Thomas; Kattner, Gerhard; Koch, Boris P (2018): Stoichiometry, polarity, and organometallics in solid-phase extracted dissolved organic matter of the Elbe-Weser estuary. PLoS ONE, 13(9), e0203260