Derivatized L-methionine having indole backbone has been anchored on polystyrene-divinylbenzene matrix and has been found to have selective binding ability for Pb(II) and Ag(I) ions at pH 8.0 and 6.5, respectively. Maximum capacity for Pb(II) at pH 8.0 is 0.35 mmol g-1 and for Ag(I) at pH 6.5 is 1.5 mmol g-1. The final resin and its precursors are fully characterized by different instrumental techniques. Detection limits (3 × standard deviation of the blank signal) were 30 ng mL-1 for Pb(II) and 38 ng mL-1 for Ag(I). Recoveries were found to be 97.4 ± 2.6% for Pb(II) at 98% confidence level and 98.2 ± 3.4% for Ag(I) at 97% confidence level. The developed procedure has been successfully applied for preconcentration of Pb(II) and Ag(I) in different environmental and biological samples. The concentration of Pb(II) was determined by flame atomic absorption spectrometry (FAAS) and that of Ag(I) ion by using a scintillation counter equipped with a well type NaI (Tl) crystal detector.
derivatized L-methionine; indole; chelating resin; polystyrene; lead; silver; FAAS; scintillation detector; application
