One-Pot Separation and Preconcentration for the Determination of Chromium Species Using an Aqueous Biphasic System

The widespread use of the trace metal chromium in industrial processes and the known toxicity of CrVI species have stimulated interest in chromium speciation analysis. However, some analytical detection systems are not suitable for the quantification of CrIII and CrVI species. In the present study, an aqueous biphasic system (ABS) was employed as an environmentally safe, simple, and economical alternative. The ABS allows the implementation of an efficient separation step before quantifying of the species of interest by flame atomic absorption spectrometry. A robust speciation and preconcentration method was developed, which can be applied to samples with a wide concentration range, without the use of any extractants and interconversion of the species during the procedure. The proposed method was successfully used to determine the chromium species present in tap, treatment plant, river, and electroplating wastewater samples. Recovery percentages of 87.9-107% were achieved, suggesting minor water matrix interference. The proposed method had acceptable limits of detection and quantification of 5.38 and 16.3 µg kg-1, respectively.