Analysis of Arsenic in Oysters Using Reversed Phase HPLC-ICPMS/ESI-Orbitrap-MS

The presence of high concentration of arsenic in marine organisms has attracted much attention over the years due to the toxicity of the element. However, only limited investigations have been carried out on the lipidsoluble arsenic species (arsenolipids) relative to the water-soluble compounds. In this study, we investigate the distribution of total arsenic and arsenolipid speciation in samples of Oysters (Ostreaedulis) collected from the local market in Aberdeen (OY-A), UK and in Port Harcourt (OY-P), Nigeria. For total arsenic determination, the samples were mineralised by microwave-assisted acid digestion and analysed using ICP-MS. The results showed significant variation in total concentrations of arsenic in Oysters from the different locations. However, analysis of the lipid extract using HPLC-ICP-MS/ESI-Orbitrap-MS showed similarity in arsenolipid profile. The speciation study is significant since toxicity of arsenic depends on the molecular forms of the element. Three arsenolipids were identified with elemental compositions consistent with arsenic fatty acids. This result could also be used to compare the relative arsenic exposures and accumulation patterns of Oysters at the different locations.