Bifunctional aminosilane-functionalized Fe3O4 nanoparticles as efficient sorbent for preconcentration of cobalt ions from food and water samples

Magnetic Fe3O4 nanoparticles were synthesized by a coprecipitation method, then their surface was covered and modified by [1-(2-aminoethyl)-3-aminopropyl]trimethoxysilane. The resulting adsorbent was used in preconcentration of Co(I (TM) I (TM)) ions prior to their determination by flame atomic absorption spectroscopy. The modified nanoparticles were characterized by Fourier-transform infrared spectroscopy, scanning electron microscopy, and vibrating-sample magnetometry techniques. Various parameters influencing the preconcentration efficiency, such as medium pH, adsorbent quantity, sample volume, and elution conditions, were optimized. Under optimum conditions, the analytical performance of the method was evaluated. The calibration curve was found to be linear from 1 to 200 mu g L-1 (R (2) = 0.99). The limit of detection was calculated to be 0.5 mu g L-1 (n = 5). The relative standard deviation was obtained as 2.5% (n = 5). Moreover, the maximum adsorption capacity of the sorbent was 32.05 mg g(-1). Kinetic and isotherm models were also studied, showing that the adsorption matched well with pseudo-second-order and Langmuir models. The ability of the developed method was proved by application for preconcentration of cobalt ions from food and water samples.