A novel aeration-assisted homogenous liquid–liquid microextration for determination of thorium and uranium in water and hair samples by inductively coupled plasma-mass spectroscopy

• Aeration-assisted homogenous liquid–liquid microextraction.
• ICP-MS combined with AA-HLLME for sensitive and selective thorium and uranium determination.
• Preconcentration and determination of thorium and uranium by excellent figure of merits.

A novel method based on aeration-assisted homogeneous liquid–liquid microextraction using high density solvent is presented, which is combined with inductively coupled plasma-mass spectroscopy in which simultaneous preconcentration and determination of thorium and uranium with arsenazo III as the chelating reagent is carried out. To achieve optimum conditions, several parameters such as pH, concentration of arsenazo III, extraction and homogenous solvent types and their volumes, salt concentration and extraction time were investigated. Under which, the calibration graphs were linear in the range of 0.5–600.0 ng L−1 for thorium and 0.3–550.0 ng L−1 for uranium. Good linearities were obtained for both analytes with R2 values larger than 0.9990. The limits of detection (LOD, 3Sb/m, n=5) of this method were 0.12 and 0.09 ng L−1, and the enrichment factors were estimated to be 370 and 410 for thorium and uranium, respectively. The proposed method was applied to determine the thorium and uranium in human hair and different environmental water samples. Acceptable recoveries ranged from 99.4% to 100.7% with standard deviation of 0.05 to 0.17.

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