Solid-phase extraction of Cu, Zn, and Mn from Nile river and tap water prior to flame atomic absorption determination

In this study, we preconcentrated Cu, Zn, and Mn from Nile river and tap water at Cairo City (Egypt) by solid-phase extraction prior to flame AAS determination. Diacetylmonoxime functionalized silica gel (DMO-SG) was used as sorbent for preconcentration/separation of metal ions. Best sorption was achieved at sample pH 6 and flow rate of 2 mL min−1. Desorption was affected by a 0.3 mol L−1 of hydrochloric acid solution. Sorption kinetic and isotherm were found to follow the pseudo-second-order and Freundlich isotherm models, respectively. The capacity was 422, 533, and 346 μg g−1 for Cu, Zn, and Mn, respectively. The limit of detection (3σ) was 0.10, 0.11, and 0.12 μg L−1 and preconcentration factor was 100, 105, and 50, respectively. The recovery ranged between 92 and 102% and RSD % varied from 2.6 to 7.4%.