Speciation of arsenic compounds in some marine algae, bivalves, and cr
ustaceans was studied by using two techniques: (i) high-performance li
quid chromatography with inductively coupled plasma mass spectrometry
detection and (ii) hydride generation atomic absorption spectrometry f
ollowing microwave-assisted digestion. Arsenosugars were identified as
the major arsenic compounds present in marine algae, whereas arsenobe
taine 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 reve
aled the presence of arsenosugars in addition to arsenobetaine in the
bivalves. The speciation of arsenic in sample extracts and ''defrost l
iquid'' from previously frozen marine animal samples revealed that up
to 48% of the total arsenic in the sample can be released in the defro
st 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. Arse
nobetaine in sample extracts that were stored at 4 degrees C for 9 mon
ths was decomposed to trimethylarsine oxide and two other unidentified
arsenic species.