Determination of Lead and Cadmium in Different Samples by Flow Injection Atomic Absorption Spectrometry Incorporating a Microcolumn of Immobilized Ammonium Pyrrolidine Dithiocarbamate on Microcrystalline Naphthalene

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