Sensitive determination of uranium using β-cyclodextrin modified graphene oxide and X-ray fluorescence techniques: EDXRF and TXRF.

β-cyclodextrin/graphene oxide (GO-β-CD) was applied for dispersive micro-solid phase extraction (DMSPE) of uranyl ions (UO) from water samples and their determination by energy-dispersive (EDXRF) and total-reflection X-ray fluorescence spectrometry (TXRF). The structure of GO-β-CD was characterized by X-ray photoelectron spectroscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, and Raman spectroscopy. The results of batch adsorption experiment indicate that the maximum recoveries for UO ions are observed at pH 4.5. The Langmuir isotherm model fits the adsorption data, which stands for the chemisorption mechanism. The obtained adsorption capacity of 87.7 mg g indicates a great potential of the synthesized adsorbent in the UO ions preconcentration. The GO-β-CD exhibits high resistance to high ionic strength (up to 2 mol L), indicating that high salinity samples can be treated with the evaluated preconcentration procedure. The obtained limit of detection values were 0.40 μg L for the EDXRF and only 0.014 μg L for TXRF analysis. The accuracy of the method was verified by analyzing certified reference material (spring water NIST-SRM 1640a) and spiked water samples (mineral, lake, river, and artificial sea water).