Determination of Trace Metals in Waters by FAAS after Enrichment as Metal-HMDTC Complexes Using Solid Phase Extraction

Abstract

A method has been described for the determination of Cu(II), Pb(II), Ni(II), Cd(II), Mn(II) and Fe(III) by flame atomic absorption spectrometry (FAAS) after preconcentration on Amberlite XAD-16 resin, using hexamethyleneammonium-hexamethylenedithiocarbamate (HMA-HMDTC) as a chelating agent, and NH 3 / NH 4 Cl buffer solution (pH 9). Influences of various analytical parameters such as pH, concentration of nitric acid, amount of analytes, diverse ions and sample volume were investigated. The relative standard deviation (RSD) and the detection limit (LOD) were found in the range of 0.8-2.9% and 0.006-0.277 µg/mL, respectively. Recoveries obtained by the column method were quantitative (>95%) at optimum conditions. The method was applied to the determination of some metal ions in seawater and wastewater samples. A high preconcentration factor (about 150 for seawater and 75 for wastewater samples) and simplicity are the main advantages of this suggested method.