A sample preparation method has been developed to detect cadmium and lead in commercial frozen
seafood samples. After being digested with concentrated HNO3 in a closed polypropylene vessel, the clear sample
solution was separated and preconcentrated by solid phase extraction using octadecyl silica membrane discs modified
with 8-hydroxyquinoline prior to determination by graphite furnace atomic absorption spectrometry (GFAAS). The
preconcentration conditions including pH, ligand quantity, eluent concentration, and volume were found to be effective
with 10.0 mg of 8-hydroxyquinoline in 2.0 ml ethanol and pH 6.0. The retained cadmium and lead were efficiently
eluted with 5.0 ml of 1.0 M HNO3 and determined by GFAAS. The detection limits for cadmium and lead were
0.073 µg/l and 0.332 µg/l, respectively. The proposed method was tested with the certified reference material, DORM-
2 (Dogfish muscle), with good agreement. The recoveries were found to be 100–103% (n = 4) for Cd and 92–108%
(n = 5) for Pb with relative standard deviation (n = 5) of 3% for Cd and 4% for Pb. The extraction was found to
be unaffected by coexisting ions. The method was applied satisfactorily to the seafood samples and trace levels of
cadmium and lead were found.