A micellar mediated novel method for the determination of selenium in environmental samples using a chromogenic reagent

A novel, simple, sensitive and rapid spectrophotometric method for the determination of selenium(iv) in an acidic medium using rhodamine B hydrazide (RBH) has been developed. The method is based on the micellar mediated oxidation of RBH by Se(iv) in an acidic medium to produce a pinkish violet color of rhodamine B, which was monitored spectrophotometrically at λmax 585 nm. The sensitivity of the method was found to increase when the reaction was performed in a micellar medium. Beer's law was obeyed in the concentration range of 0.002-0.032 μg mL-1. The reaction variables such as time, temperature, reagent concentration, and acidity have been optimized for the reaction. Sandell's sensitivity and molar absorptivity for the reaction system were found to be 0.00004 μg cm-2 and 42.52 × 106 L mol-1 cm-1, respectively. The developed method was successfully applied for the determination of Se(iv) in several real samples with quantitative results.