A new flow injection on-line preconcentration system adapted to flame atomic absorption
spectrometry (FAAS) for lead and cadmium determination at the μg L–1 level was developed.
Ammonium pyrrolidine dithiocarbamate was immobilized on microcrystalline naphthalene and
was used as sorbent material in microcolumn preparation. Deposition of lead and cadmium was
effected by processing a standard or solution of analytes at pH = 2–9 on the column. Injection
of 500 μL of ethanolic solution of acetic acid (0.5 mol L–1) and hydrochloric acid (0.25 mol L–1)
served to elute the retained species to atomic absorption spectrometry (AAS). A sample volume
of 25 mL resulted in preconcentration factors of 65 and 53 for lead and cadmium, respectively,
and precision at 60 μg L–1 was 2.7 % and 3.6 % (RSD) for lead and cadmium, respectively.
The procedure was applied to tap water, river water, sea water, pine leaf and human blood
samples. The accuracy was assessed through recovery experiments and independent analyses
by furnace AAS.