FLOW-INJECTION ONLINE CO-APDC COPRECIPITATION PRECONCENTRATION AND DETERMINATION OF LEAD AND COPPER IN SEAWATER WITH GRAPHITE-FURNACE ATOMIC-ABSORPTION SPECTROMETRY

A method of the flow-injection (FI), on-line, CoAPDC coprecipitation for the preconcentration and determination of Pb and Cu in seawater with graphite furnace atomic absorption spectrometry (GFAAS) has been developed. A precipitate collector consisting of a PTFE membrane on a polypropylene support filtering cup combined with an autosampler for a graphite furnace was designed. MIBK was used as for FI, on-line, dissolution of Co-APDC coprecipitation. Graphite furnace atomic absorption spectrometric determination of the analyte was performed in parallel with the preconcentration of the next sample. Enrichment factors of 26 for lead and copper were attained using 30 s precipitate collection time, at a sample flow rate of 5 mL/min. The detection limits (3sigma) were 0.005 and 0.001 mug/L for lead and copper, and the RSDs were 4.8% and 3.2%, respectively. Recoveries of lead and copper in seawater were 94%. The technique has been applied to seawater sample analysis.