Solid-phase extraction of trace Ni(II) ions on ethylenediamine-silica material synthesized by sol-gel method

A solid-phase extraction method using ethylenediamine-silica (EDA-SIL) material for the determination of Ni(II) ions at trace level by flame atomic absorption spectrometry (FAAS) was presented in this study. EDA-SIL was synthesized with 3-(2-aminoethylamino) propyltrimethoxysilane (EDA-silane) and tetraethyl orthosilicate by sol-gel technique performing acidic hydrolysis and basic gelation procedure. EDA-SIL was characterized by FT-IR and C, H, and N elemental analysis. Solid-phase extraction of Ni(II) ions was carried out using mini column filled with EDA-SIL. The important variables governing the recovery of Ni(II) including pH, flow rate, eluent type, eluent volume, and matrix ions were studied. At the optimum preconcentration conditions, the recovery of Ni(II) was found to be 100 +/- 3% at 95% confidence level. The detection limit of Ni(II) was calculated based on the three times of standard deviation of blanks and found to be 0.32 ng mL(-1) using a preconcentration factor of 50. The developed method was validated using certified water samples (Ontario Lake water, NWTMDA-54.4) and applied to synthetic sea water samples for the determination of Ni concentration by FAAS.