For Hg analysis, approximately 200 mg of the cleaned powder was
used without dissolution or further preparation (Lamborg et al., 2013).
To investigate signal replication, Hg concentrationswere analyzed from
two adjacent corals collected from CH. Determination of low-level
Hg by calcination–isotope dilution ICP-MS is discussed in Lamborg
et al. (2013). In brief, the coral powder was heated to 850 °C while
in-line with the ICP and an enriched 200Hg0 vapor standard, and
the 202Hg/200Hg ratio integrated in the resulting chromatograph.
Primary signal calibration for Hg was achieved using gas injections
from a natural isotope abundance saturated vapor standard. The
absolute instrument detection limit was approximately 200 amol
(10−18 mol), with a practical limit of detection of 2000 amol (Lamborg
et al., 2013).