Current methods for determining iron in seawater
involve extractive chelation and preconcentration
from large volumes (0.5±2 l) of ®ltered seawater
[21,22]. Subsequent laboratory analysis is generally
performed using graphite furnace atomic absorption
spectrometry. This method suffers from many disadvantages.
It is tedious, has many sample handling
stages (thus increasing the risk of contamination),
large sample volumes are required in order to achieve
low detection limits and the precision is poor. The
technique provides no information relating to the
oxidation state of the metal and, without a clean
container laboratory, is clearly impractical for shipboard
analyses