Dipyridylamine-modified nanoporous silicas as new sorbents for the separation and pre-concentration of palladium

Nanoporous silicas of the type SBA-15 (Santa Barbara Amorphous) and MCM-48 (Mobile Composition of Material) were modified with dipyridylamine (dipy) and used as solid phases for the extraction of Pd(II) ions. The experimental conditions (pH, sample and eluent flow rates, type and quantity of eluent) were optimized. The recovery values were similar to 99.7 and similar to 93.4% for dipy-MCM-48 and dipy-SBA-15, respectively, the limits of detection were < 0.08 and < 0.11 ng L-1, the pre-concentration factors were 725 and 550, and the adsorption capacity was > 78 mg g(-1). The procedure was applied to the preconcentration of Pd(II) in real samples.