The Pb2þ adsorption and protein exclusion were appraised in the optimized system, using a human serum sample fortified with 100 mg L1 of Pb2þ. The atomic (Pb2þ) and molecular (proteins) absorptions were simultaneously monitored by the TS-FF-AAS and by an ultraviolet detector (280 nm) coupled at the end of the cleaning solution tube (see Fig. 1). The results are shown in Fig. 6. As it can be seen, the end of the molecular absorption peak was observed in about 4.5 min, which was sufficient to exclude all of the proteins present in the sample (exclusion ability of about 100%.