EXAMPLE: Traces of Fe in Sea Water
This is an example of sorbent extraction sample cleanup that has found wide use in oceanography and environmental analysis.
Matrix removal and accumulation of iron is achieved in the first step by passing buffered sea water sample through a microcolumn 8-hydroxyquinoline immobilized on the solid support. Iron is captured as the Fe chelate is adsorbed on the column (STEP #1).
NOTE: The second 8- HQ column is used to purify DPD reagent to reduce a blank that is due to the presence of Fe impurities in the reagent.
For STEP #2 the valve is switched so that the acid carrier solution elutes Fe from the column. Next, the eluted Fe solution is buffered and mixed with purified DPD and hydrogen peroxide .
Iron catalyzes the oxidation of colorless DPD into red colored DPDQ (B) during the passage through a 2m long reaction coil.
C.I. Measures, J. Yuan, J.A. Resing, Marine Chemistry, 59 (1995) 3-12
1.3.11.
