Occurrence of arsenobetaine and arsenocholine in micro-suspended particles

A large quantity of seawater has been passed through a plankton net of 5 μm or 100 μm pore-size. The precipitated micro-suspended particles in each of the filtrates were collected and subjected to a microscopic examination and analysis by HPLC-ICP-MS. While a small number of diatoms are included in the particles passed through the 100 μm net, no organisms were observed in the particles passed through the 5 μm net. In the particles through 5 μm, arsenobetaine and inorganic arsenic(III) were the major organo-arsenic compounds, a small amount of arsenocholine being also detected. On the other hand, inorganic arsenic(III) as the major arsenical, arsenobetaine and arsenic(V) were found in the particles passed through 100 μm poresize.