At the onset of the 2010 Gulf oil spill, analytical methods for the quantification of the surfactants in Corexit did not exist in the peer-reviewed literature. To date, only a single study reports the presence of bis-(2-ethylhexyl) sodium sulfosuccinate (DOSS) in deep-sea Gulf sediment collected in 2010 from a single location. There are no data on the occurrence of DOSS in association with settling solids (i.e., sediment-trap solids). To address this data gap, DOSS was initially quantified by liquid chromatography tandem quadrupole mass spectrometry (LC-MS/MS) in sediment and sediment-trap solids collected from multiple sites in the Gulf between 2010 and 2013. However, interferences confounded analyses using only a quadrupole (MS/MS) system; therefore, a LC-high mass accuracy quadruple time of flight mass spectrometry (LC-QTOF-MS) method was developed. The LC-QTOF method was validated and applied to eight representative samples of sediment and of sediment-trap solids. The presented method quantifies DOSS in solids of marine origin at concentrations above the limit of quantification of 0.23 μg kg-1 with recoveries of 97 ± 20 % (mean ± 95 CI). Gulf sediment and sediment-trap solids gave DOSS concentrations of <LOQ-25 and 1.5-6.3 μg kg-1, respectively. Graphical Abstract Sediment core and sediment trap materials were collected in the Gulf and analyzed for DOSS by LCQTOF.
Keywords: Corexit; DOSS; Dioctyl sulfosuccinate; QTOF; Sediment; Sediment trap.