Speciation of trace amounts of Sb(iii) and Sb(v) in environmental water using inductively coupled plasma mass spectrometry after magnetic solid-phase extraction with rGO/Fe₃O₄

We developed an approach of magnetic dispersive solid-phase extraction (MSPE) based on magnetic graphene nanocomposite rGO/Fe3O4 for the determination of trace Sb(III) and Sb(V) using inductively coupled plasma mass spectrometry (ICP-MS). Scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR) were used to characterize the sorbent. The adsorption behavior of Sb(III) and Sb(V) on rGO/Fe3O4 was investigated. The results showed that the adsorption capacity of Sb(V) was nearly zero at pH = 9, while Sb(III) could be well adsorbed on rGO/Fe3O4. The magnetic SPE parameters including pH, adsorbent dosage, eluent type, and volume were optimized. The detection limit of Sb(III) under ideal conditions was 6 ng L-1, and the relative standard deviation was 7.6% (c = 1 g L-1, n = 7). The technique was used to identify Sb(III) at trace levels in environmental water samples, and its validity was examined by recovery experiments and the examination of an approved reference material.