DIRECT DETERMINATION OF COPPER IN SEA-WATER WITH A GRAPHITE-FURNACE ATOMIC-ABSORPTION SPECTROMETER

Copper in sea-water was determined directly using a graphite furnace atomic absorption spectrometer (GFAAS) with a stabilized temperature platform and matrix modification through addition of ammonium nitrate. Both deuterium background correction and Zeeman effect background correction were used and compared. The detection limit was 0.3-0.4 mug/l with injection,of a 20 mul aliquot of sea-water sample. The matrix interference was removed completely, so that a calibration curve using deionized water could be used. The detection limit was further reduced to 0.07 mug/l using multiple injection (injection of five 20 mul aliquots of sea-water). The accuracy and precision of the developed methods were confirmed by analysis of three kinds of certified reference sea-water.