Resumen de Spectrophotometric determination of bismuth in water samples by dispersive liquid-liquid microextraction after multivariate optimization based on box-behnken
Ali Niazi, Sima Habibi, Majid Ramezani
A new simple and rapid dispersive liquid-liquid microextraction has been applied to preconcentration trace levels of bismuth as a prior step to its determination by spectrophotometric detection. In the proposed method, dithizone was used as a chelating agent, and tetrachloride carbon and ethanol are selected as extraction and dispersive solvent. The optimization strategy is carried out by using two level full factorial designs. Results of the two level full factorial design (2(4)) based on an analysis of variance demonstrated that the pH, concentration of dithizone, amount of dispersive and extraction solvents were statistically significant. Optimal condition for four variables: pH, concentration of dithizone, amount of dispersive and extraction solvents are obtained by using Box-Behnken design. Under the optimum conditions, the calibration graphs were linear in the range of 5-300 ng mL-1 with detection limit of 1.6 ng mL-1 (3δB/m) and the enrichment factor of this method for bismuth reached at 150. The relative standard deviation (R.S.D.) is 2.3% (n = 5, c = 50 ng mL-1). The method is successfully applied to the determination of trace amount of bismuth in water samples.
