ICP-OES Determination of Trace Metal Ions after Preconcentration Using Silica Gel Modified with 1,2-Dihydroxyanthraquinone

A new chelating matrix was prepared by immobilizing 1,2-dihydr-oxyanthraquinone, or alizarin (AZ), on silica gel modified with (3-aminopropyl)trimethoxysilane. The matrix was characterized by FTIR spectroscopy and elemental analysis. The new matrix was used to preconcentrate Cd(II), Cu(II), Ni(II), Pb(II) and Zn(II) prior to their determination by inductively coupled plasma optical emission spectrometry (ICP-OES). The optimum pH was 5 and the optimum extraction time was approximately 15 minutes using the batch method. Common electrolytes and metal ions did not interfere with the separation and determination of the analytes. The adsorption capacity of the new sorbent was 67.4, 163.5, 212.8, 76.4 and 180.3 μmol/g for Cd(II), Cu(II), Ni(II), Pb(II) and Zn(II), respectively. The relative standard deviations (RSD) were less than 3.0%. This method allowed for successful separation and preconcentration of trace metal ions in different water samples with satisfactory results.