ONLINE PRECONCENTRATION OF LEAD AND CADMIUM FOR FLAME ATOMIC-ABSORPTION SPECTROMETRY USING A FLOW-THROUGH ELECTROCHEMICAL MICROCELL

A method was developed for the trace determination of lead and cadmium by flame atomic absorption spectrometry (FAAS) with electrochemical p reconcentration. Both metals were deposited on the glassy-carbon elect rode in a flow-through microcell of volume 3 mu l. At a consumption of a 3 mu I sample volume, the procedure resulted in an enhancement fact or of more than 20 and yielded a detection limit of 1 mu g l(-1) for P b and 0.08 mu g l(-1) for Cd. The relative standard deviation (n=12) w as 2.1% at the 100 mu g l(-1) level for Pb and 3.2% at the 8 mu g l(-1 ) level for Cd. Results obtained for the standard reference material, water SRM 1643c, were in good agreement with the certified values. (C) 1997 Elsevier Science B.V.