Preconcentration on metal organic framework UiO-66 for slurry sampling hydride generation-atomic fluorescence spectrometric determination of ultratrace arsenic

In this work, metal organic framework (MOF) UiO-66 with strong stability in water was synthesized and used for the preconcentration of ultratrace arsenic in environment water and the precipitated UiO-66 was converted to slurry for direct determination with hydride generation-atomic fluorescence spectrometry (HG-AFS). Factors affecting the adsorption of arsenic by UiO-66, including pH, adsorption time, stability of UiO-66, masking agents together with the optimum conditions of HG-AFS were investigated in detail. The performance of UiO-66 for adsorbing arsenic was excellent at room temperature over a wide range of pH from 1 to 11, and adsorption efficiencies of >   95% could be achieved within only 5   min. Meanwhile, since conventional digestion process is avoided, the slurry sampling method is fast and convenient with greatly reduced matrix interference. Under the optimum conditions, it shows a good linear relationship between AFS intensities (I) and the concentrations of arsenic (C) (I   =   547C   +   61) with linear correlation coefficients better than 0.99. A precision of 3% (RSD%, n   =   11) at 1   ng/mL and a limit of detection (LOD) of 0.0002   ng/mL were obtained.