Spectrophotometric determination of Sb(III) and Sb(V) in biological samples after micelle-mediated extraction.

This work presents a micelle-mediated extraction method for simultaneous preconcentration and determination of Sb(III) and Sb(V) species in biological samples as a prior preconcentration step to their spectrophotometric determination. The analytical system is based on the selective reaction between Sb(III) and bromopyrogallol red (BPR) in the presence of cetyltrimethylammonium bromide (CTAB) and potassium iodide at pH 6.4. Total Sb concentration was determined after reduction of Sb(V) to Sb(III) in the presence of potassium iodide and ascorbic acid. The optimal extraction and reaction conditions were studied and the analytical characteristics of the method (e.g., limit of detection, linear range, preconcentration factor, and improvement factors) were obtained. Linearity for Sb(III) and Sb(V) were obeyed in the range of 0.2-20.0 ng mL(-1) and 0.4-25.0 ng mL(-1), respectively. The detection limit for the determination of Sb(III) and Sb(V) were 0.05 ng mL(-1) and 0.08 ng mL(-1), respectively. The interference effect of some anions and cations was also studied. The method was applied to the determination of Sb(III) in the presence of Sb(V) and total antimony in blood plasma and urine samples.