FATE OF MERCURY IN THE ARCTIC Michael Evan ... - COGCI

Fate of Mercury in the Arctic 59
weighed into Ni sampling boats that have been blanked in the AMA 254 prior to use. Samples are
then placed into the machine, one sample at a time. They enter a combustion chamber where they
are dried, then are thermally decomposed in a stream of pure oxygen. Gases from the thermal
decomposition are then carried in the oxygen stream into a catalyst chamber, which fully
decomposes the gases at a temperature of 750°C. Mercury is thereafter carried with the oxygen
stream onto and trapped on a gold amalgamator situated immediately after the catalyst chamber.
The amalgamator is then heated to 500°C to release the Hg, which is carried with the oxygen stream
into a cuvette, and mercury determined using atomic absorption spectrometry, with the mercury
absorption line at 254 nm.
The detection limit of the instrument is 0.01 ng Hg and the working range is 0.05-600 ng Hg,
with reproducibility being