DETERMINATION OF CD, CU, AND PB IN ESTUARINE WATER AND FERTILIZERS BYGRAPHITE-FURNACE AAS WITH FLOW-INJECTION SORBENT EXTRACTION

Trace cadmium, copper, and lead in estuarine water and digested agricu ltural fertilizers, both containing high concentrations of dissolved s alts, were determined for two certification campaigns, respectively, b y graphite furnace atomic absorption spectrometry after flow injection sorbent extraction preconcentration-separation using octadecyl functi onal groups (C-18), bonded silica gel as sorbent, diethyldithiophospha te as chelating agent, and ethanol as eluent. While the analyte enrich ment was in the flow system, the salt matrices were removed effectivel y through analyte-selective extraction and column rinsing before eluti on. The final measurements were done with deuterium arc background cor rection. The results were in good agreement with those from other samp le pretreatment and/or final detection techniques and thus with the fo rmal certified or indicative values, demonstrating the accuracy and re liability of the analytical method.