Dispersive solid phase extraction of Ni2+ using graphene oxide-polyethylenimine nanocomposite as an efficient adsorbent in different real samples; Response surface methodology based on central composite design optimisation

Abstract

ABSTRACT An efficient modified graphene oxide adsorbent was used for dispersive solid phase extraction of trace levels of Ni2+ followed by its determination using electrothermal atomic absorption spectrometry (ETAAS). Graphene oxide modified polyethylenimine nanocomposite (GO-PEI) was used as an adsorbent and characterised by the Fourier Transform-Infrared Spectrophotometry (FT-IR), Field Emission Scanning Electron Microscopy (FE-SEM), Energy Dispersive X-Ray Spectroscopy (EDX) and X-Ray Diffraction Analysis (XRD). In order to optimise the critical parameter affecting the extraction efficiency of Ni2+, the response surface methodology based on central composite design (RSM-CCD) was used. Under the optimum condition, the calibration curve was found to be linear in the range of 0.1–2.0 µg L−1 with a correlation coefficient of 0.9997. The inter-day relative standard deviation (RSD) was 3.5% based on seven replicate analysis of 1.0 µg L−1 Ni2+ and the limit of detection (LOD) was 0.018 µg L−1 (n = 8). The accuracy of the proposed method was checked by the analysis of certified reference material-trace metals in drinking water (CRM-TMDW) and then it was successfully applied for determination of trace levels of Ni2+ in different real samples.