Determination of heavy metals by electrothermal atomic absorption spectrometry after electrodeposition on a graphite probe

Traces of heavy metals were separated and preconcentrated electrochemically at a controlled potential on the graphite ridge probe. After the electroly sis, the electrode-probe was inserted in the graphite furnace for atomizati on of metal deposit by an automatic system. Conditions for the electrodepos ition, such as pH of solutions, the deposition potential and concentration of electrolyte, were optimized. Detection limits improved with increased ti me of electrodeposition and were 16 ng l(-1) Cu, 1.0 ng l(-1) Cd, 6.0 ng l( -1) Pb, 64 ng l(-1) Ni, 14 ng l(-1) Cr(III) and 17 ng l(-1) Cr (VI) for a 1 0-min deposition. This method was applied for the determination of copper, cadmium, lead, nickel and of chromium species in seawater. (C) 1999 Elsevie r Science B.V. All rights reserved.