SPECIATION OF ARSENIC COMPOUNDS IN SOME MARINE ORGANISMS

Speciation of arsenic compounds in some marine algae, bivalves, and crustaceans was studied by using two techniques: (i) high-performance liquid chromatography with inductively coupled plasma mass spectrometry detection and (ii) hydride generation atomic absorption spectrometry following microwave-assisted digestion. Arsenosugars were identified as the major arsenic compounds present in marine algae, whereas arsenobetaine was the dominant arsenic species present in crab and shrimp. In contrast to most previous reports, which claimed arsenobetaine as the only major arsenic species present in marine bivalves, this study revealed the presence of arsenosugars in addition to arsenobetaine in the bivalves. The speciation of arsenic in sample extracts and ''defrost liquid'' from previously frozen marine animal samples revealed that up to 48% of the total arsenic in the sample can be released in the defrost liquid. Arsenic species found in the defrost liquid were identical with those in the sample extracts. Changes in arsenic speciation were observed in the sample extracts that were stored for a long term. Arsenobetaine in sample extracts that were stored at 4 degrees C for 9 months was decomposed to trimethylarsine oxide and two other unidentified arsenic species.