RESUMO
A green, facile, fast, and sensitive liquid-phase microextraction method is presented for the extraction and preconcentration of hemin in the presence of free iron ions prior to flame atomic absorption spectroscopic determination. In this technique, an anion-functionalized task-specific ionic liquid is used as the extracting solvent. The interface between the extracting solvent and the bulk aqueous phase containing hemin is enormously enlarged by dispersing the ionic liquid to the aqueous phase with the help of ultrasound radiation. Hemin is selectively extracted into the ionic liquid after interaction with the functional group of the ionic liquid. Then, the concentration of the extracted hemin is determined through the absorbance of the iron ions contained in the hemin structure using flame atomic absorption spectroscopy. Different experimental parameters affecting the extraction efficiency have been optimized. Under the optimized conditions, the proposed method has a hemin concentration linear range of 0.020-0.80 mg/L with a detection limit of 0.0080 mg/L. This method has been successfully applied to the extraction and determination of hemin in human serum and supernatant samples.
