Atomic absorption spectrometric determination of Al3+ and Cr3+ after preconcentration and separation on 3-mercaptopropionic acid modified silica coated-Fe3O4 nanoparticles

A new magnetic solid sorbent was synthesized using 3-mercaptopropionic acid grafted silica modified Fe3O4 magnetic nanoparticles. The sorbent was characterized by SEM, XRD, and FT-IR and used for solid phase extraction of Al3+ and Cr3+ ions. Al3+ and Cr3+ ions were measured by graphite furnace and flame atomic absorption spectrometry, respectively. The optimal extraction/preconcentration conditions including pH of sample solution, desorption conditions (type, concentration, and volume of the eluent), sonication time, sample volume, adsorbent amount, and interfering ions were studied. Under optimal conditions, the detection limits of 0.09 and 0.19 ng mL(-1) were obtained with a relative standard deviation (RSD%) of 2.1-5.2% for Al3+ and Cr3+ ions, respectively. The enrichment factors were found to be 99 and 92 for Al3+ and Cr3+ ions, respectively. The effects of various cationic interferences on percent recovery of Al3+ and Cr3+ ions were studied. The developed method- was successfully applied for selective extraction and preconcentration of trace amounts of Al3+ and Cr3+ in biological and environmental samples.