Trace analysis of Pb(II) in milk samples by Fe3O4@SiO2@3-chloropropyltriethoxysilane@o-phenylendiamine nanoparticles as an unprecedented adsorbent for magnetic dispersive solid phase extraction

Abstract

In the present work, a magnetic dispersive solid-phase extraction method followed by flame atomic absorption spectrometry was used for extraction, preconcentration and determination of trace amounts of Pb(II) in milk samples. Fe3O4@SiO2@3- chloropropyltriethoxysilane@o-phenylendiamine nanoparticles were synthesised and used as the adsorbent in the extraction procedure. The effective parameters of the extraction efficiency comprising pH of the sample solution, sorbent amount, extraction time, acidic concentration of the eluent and desorption time were optimised using a face-centred central composite design. Under the optimal conditions, the applied method offered suitable linearity in the range of 2.0-250 ng mL-1, the limit of detection as low as 0.11 ng mL-1, and high preconcentration factor of 66. The precision of the proposed method was evaluated by calculating the intra-day and inter-day relative standard deviation, which were <3.4 and 5.5%, respectively. The applicability of the method in real sample analysis was tested by analysing bovine milk samples. The relative recoveries in the range of 81.6-97.2% showed the suggested method is of appropriate accuracy in real sample analysis.