Trace cadmium, copper, and lead in estuarine water and digested agricultural fertilizers, both containing high concentrations of dissolved salts, were determined for two certification campaigns, respectively, by graphite furnace atomic absorption spectrometry after flow injection sorbent extraction preconcentration-separation using octadecyl functional groups (C18), bonded silica gel as sorbent, diethyldithiophosphate as chelating agent, and ethanol as eluent. While the analyte enrichment was in the flow system, the salt matrices were removed effectively through analyte-selective extraction and column rinsing before elution. The final measurements were done with deuterium arc background correction. The results were in good agreement with those from other sample pretreatment and/or final detection techniques and thus with the formal certified or indicative values, demonstrating the accuracy and reliability of the analytical method.
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|Published - Jul 1996