Chemically functionalized silica gel with alizarin violet and its application for selective solid-phase extraction of lead from environmental samples

A new material for solid-phase extraction of Pb(II) was prepared using chemically functionalized silica gel with alizarin violet. This material is stable in 6 mol L−1 of HCl, 6 mol L−1 of H2SO4, common organic solvents and pH 1.0–9.0 aqueous solutions. The influences of analytical parameters including pH of the aqueous solution, amount of the functionalized silica gel, stirring time and flow rates of sample solutions on the quantitative recoveries of Pb(II) were investigated. At the optimum conditions, Pb(II) can be adsorbed with almost 100.0% retention, the adsorption equilibration for Pb(II) was achieved within 15 min, and the adsorption capacity of the sorbent for Pb(II) is 3.45 mg g−1 of dry functionalized silica gel. For Pb(II) solution of 10 ng mL−1, the pre-concentration factor is as high as 500, and the recovery is higher than 92%. The new solid-phase extractant has been used for the pre-concentration of low level of Pb(II) in water and soil samples with high recoveries. The standard reference water sample (GSBZ 50009-88(2)) was introduced for accuracy and precision of analytical data.