Preconcentration and analysis of Rhodamine B in water and red wine samples by using magnesium hydroxide/carbon nanotube composites as a solid-phase extractant.

Abstract

A convenient and accurate analysis approach that combined solid-phase extraction and high-performance liquid chromatography was developed to determine the amount of Rhodamine B in red wine and Xiang-jiang river water samples. A novel composite, magnesium hydroxide/carbon nanotube composites, was synthesized and used as the solid-phase extractant for the preconcentration/analysis of Rhodamine B. Magnesium hydroxide/carbon nanotube composites, which combined the merits of carbon nanotubes and magnesium hydroxide, exhibited acceptable adsorption and desorption efficiencies for Rhodamine B. The linear range of the proposed solid-phase extraction with high-performance liquid chromatography method for Rhodamine B was 0.05-20.0 mg/L, with a limit of detection of 3.6 μg/L. The precision and reproducibility of the developed solid-phase extraction with high-performance liquid chromatography method and the batch-to-batch reproducibility of the solid-phase extractant were also validated at spiking levels of 0.5 and 2.0 mg/L. The recovery of Rhodamine B was 94.33-106.7%, and the recovery relative standard deviations of the intra- and interday precisions were ≤ 3.83 and ≤ 6.01%, respectively. The relative standard deviation of the batch-to-batch reproducibility was ≤ 7.98%.