Aspartic acid-modified magnetic nanoparticles as an ideal sorbent for solid phase extraction of Pb in water samples prior to ICP-OES determination

Abstract

The present study will consider the application of aspartic acid-coated Fe3O4 as a sorbent for solid-phase extraction of trace amounts of Pb using inductively coupled plasma optical emission spectrometry. Magnetic nanoparticles (MNPs) of Fe3O4 possess a high potential for modification with different organic and inorganic compounds. Using an amino acid (in this case, aspartic acid) as a nontoxic modifier, without an organic solvent, could provide a number of environmentally friendly applications in the field of green chemistry. By using modified MNPs as a sorbent, the separation of metal ions from an aqueous sample solution was easily performed by an external magnet without centrifuging or filtering. An elution step was accomplished by using a 2 mol L−1 nitric acid solution for introducing the desorbed analyte to ICP-OES. Different parameters influencing on the extraction efficiency, such as pH, volume of the modifier, extraction and elution time, types and concentrations of eluent were investigated and optimized. Under the optimized conditions, the detection limit for Pb was 0.6 μg L−1 and the calibration curve showed linearity in the range of 1–600 μg L−1. The relative standard deviation (RSD, C = 300 μg L−1, n = 5) was 2.8%. The sorption capacity of the sorbent was found to be 19.9 mg g−1. The sorbent exhibited good stability and high adsorption capacity for lead ions. The applicability of the sorbent was examined by a real sample and the results were satisfactory.