Copper-chitosan modified with Graphene oxide adsorbent for dispersive micro solid phase extraction of traces nickel from water and food samples

The current study presents a new insight into separation of Ni (II) by preconcentration method from water and food samples prior to atomic flame absorption spectrometry analysis. A Cu-chitosan modified Graphene oxide adsorbent was used for micro-solid phase extraction of Ni (II). The synthesized nanocomposite was subjected to characterization by FTIR (Fourier transform infrared spectroscopy), XRD (X-ray diffraction), FESEM (Field emission scanning electron microscope), SEM-EDX (Scanning electron microscopy-energy dispersive X-ray analysis), TGA (thermogravimetric analysis) and BET (Brunauer-Emmett-Teller) analysis to confirm the qualitative characteristics of the material prior to extraction process. Crucial analytical parameters such as pH, adsorbent dosage, adsorption studies and sample volume were investigated and optimized. The quantitative recovery and Relative standard deviation below 5% were obtained. The Limit of detection (LOD) and Limit of quantification (LOQ) were 0.072 mg kg -1 and 0.239 mg kg -1 respectively. To determine the greenness of the process two analytical parameters were tested, namely, analytical GREENness and AGREEprep, resulting in 0.73 and 0.70 respective grades. The proposed method presents a moderate eco-friendly and facile process. The preconcentration factor obtained for Ni (II) was 40. To validate the effectiveness of this work, the dµ-SPE method was applied to two different standard reference materials, BCR-701 lake sediment (Belgium) and TMDA-54-6 (Canada) certified water reference material. • A green, simple and rapid dµ-SPE method was developed using Cu-Chitosan@GO nanocomposite for the enrichment of Ni (II). • The method showed excellent sensitivity with a very low LOD: 0.072 mg kg -1 and LOQ: 0.23 mg kg -1 • High preconcentration factor (40) and good precision were obtained with RSDs of 1.1% for Ni (II). • The nanocomposite material provided high adsorption efficiency and selectivity, even in complex sample matrices. • The method was successfully applied to trace metal determination in food and water samples with reliable results.