Determination of Se(IV) using solidified floating organic drop microextraction coupled to ultrasound-assisted back-extraction and hydride generation atomic fluorescence spectrometry

A method is presented for matrix separation, preconcentration and determination by hydride generation atomic fluorescence spectrometry of trace amounts of Se(IV). It is based on solidified floating drops of 1-undecanol that are capable of extracting the target analyte after chelation with a water soluble ligand and subsequent ultrasound-assisted back-extraction into a aqueous solution. Hydride generation was then accomplished by reaction with a solution of sodium borohydride. Under optimized conditions, an enrichment factor of 15 and a linear calibration plot in the range from 0.01 to 5.0 μg L−1 were achieved using a 10.0 mL sample. The detection limit (3σ) is 7.0 ng L−1, and the relative standard deviation (RSD) is 2.1% at 1.0 μg L−1 (n = 11). The method was applied to determination of Se(IV) in different real water samples through recovery experiments and subsequently validated against two certified reference materials.