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Graphene oxide/Fe3O4/polyaniline nanocomposite as an efficient adsorbent for the extraction and preconcentration of ultra‑trace levels of cadmium in rice and tea samples Elias Aboobakri1 · Moslem Jahani2  Received: 8 July 2020 / Accepted: 20 August 2020 © Springer Nature B.V. 2020

Abstract The magnetic graphene oxide–polyaniline (MGOPA) nanocomposite was synthesized through oxidative polymerization of aniline and at the presence of F ­ e3O4– GO. The composite was characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction analysis, and vibrating sample magnetometry. The as-synthesized adsorbent was used for the extraction and preconcentration of the ultra-trace amount of cadmium, followed by electrothermal atomic absorption spectrometry detections. Different parameters, in particular sample pH, adsorbent dose, sample volume, adsorption time, eluent type, and desorption time, were investigated. The optimum conditions were pH 8, a sample volume of 40 mL, 4.0 × 10–3 g of MGOPA, and 2 mL of nitric acid solution (2.0 mol ­L−1) as eluent. The responses were linear in the range of 1.0 × 10–2–1.5 × 10–1  µg ­L−1 with a detection limit of 3.6 × 10–3 µg ­L−1 and a relative standard deviation of 4.2% at 5.0 × 10–2  µg ­L−1. Also, excellent recoveries (90–95%) were obtained with an enrichment factor of 400. Further studies showed that the adsorption of Cd(II) onto the MGOPA follows the Langmuir isotherm with the maximum adsorption capacity of 1.4 × 102 mg g−1. The proposed method was successfully used for the determination of cadmium in different tea and rice samples.

* Moslem Jahani [email protected]; [email protected] 1

Department of Chemistry, Faculty of Sciences, Ferdowsi University of Mashhad, Mashhad, Iran

2

Department of Food Chemistry, Research Institute of Food Science and Technology (RIFST), Mashhad, Iran



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E. Aboobakri, M. Jahani

Graphic abstract

Keywords  Hybrid materials · Magnetic nanoparticle · Cadmium · Food samples · Electrothermal atomic absorption spectrometry Abbreviations EF Enrichment factor; ETAAS Electrothermal atomic absorption spectrometry; FAAS Flame atomic absorption spectrometry; FT-IR Fourier transform infrared spectroscopy; GO Graphene oxide; HOAc Acetic acid; LOD Limit of detection; MGOPA Magnetite graphene oxide–polyaniline; MSPE Magnetic solid-phase extraction; PANI Polyaniline; RSD Relative standard deviation; SEM Scanning electron microscopy; SPE Solid-phase extraction; VSM Vibrating sample magnetometer; WHO World health organization; XRD X-ray diffraction analysis

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Graphene oxide/Fe3O4/polyaniline nanocomposite as…

Introduction Contamination with heavy metal ions is one of the serious environmental problems, which poses a considerable threat to human health and our ecosystem [1, 2]. Cadmium (Cd) is a highly poisonous metal and leads to progressive or irreversible renal injury and also to kidney failure and death [3, 4]. Cadmium is regarded as a priority pollutant by the US Environm