“…The basic principle of SPE of trace metal ions is the transfer of analytes from aqueous phase to the active sites of solid phase. For this purpose, various adsorbents including activated carbon [15,16], silica gel [17], microcrystalline naphthalene [18,19], C 18 cartridges [20], Chelex-100 [21], Alumina [22], polyurethane foam [23,24] have been used.…”