Cu2O-CuO ball like/multiwalled carbon nanotube hybrid for fast and effective ultrasound-assisted solid phase extraction of uranium at ultra-trace level prior to ICP-MS detection.

Multiwalled carbon nanotube/Cu2O-CuO ball like hybrid material (MWCNTs/Cu2O-CuO) synthesized using of a green hydrothermal process was evaluated as a new sorbent for solid phase extraction of uranium with inductively coupled plasma mass spectrometry (ICP-MS). According to our best knowledge, this new material was synthesized and used as solid phase extraction adsorbent for the first time in the literature. The characterization of new hybrid material was carried out using Raman spectroscopy, X-ray diffraction (XRD) and scanning electronic microscopy techniques (SEM, SEM-EDX and SEM-Mapping). The characterization results demonstrated that the new hybrid nanostructure was successfully obtained. The ultrasound-assisted solid phase extraction (UA-SPE) procedure was performed using 100 mg of new hybrid sorbent, 1000 μL of a 0.1% (w/v) solution of α-benzoin oxime and 2000 μL of phosphate buffer at pH 7.0 for separation and preconcentration of uranium. Uranium was eluted with 2 M HCl and the levels of uranium was measured by using ICP-MS. The linearity was observed between 2.5 and 100 ng mL-1 concentration range with a good correlation coefficient (r = 0.999, n = 7). The obtained limit of detection and quantitation values were 0.52 and 1.70 ng mL-1, respectively. Under optimum conditions, the preconcentration factor (PF) was calculated as 13.3. The accuracy of the developed method was assessed by analyzing of TMDA-62.2, TMDA-70.2 (Environment Canada) and GBW-07423 certified reference water and soil materials. The proposed UA-SPE-ICP-MS procedure developed with MWCNTs/Cu2O-CuO hybrid material was successfully applied to the analysis of uranium at ultra-traces levels in environmental water and geological rock samples.