Polyaniline-coated cerium oxide nanoparticles as an efficient adsorbent for preconcentration of ultra-trace levels of cadmium (ІІ) followed by electrothermal atomic absorption spectrometry

Abstract

For the first time, polyaniline-coated cerium oxide nanoparticles were synthesized in alkaline media and applied for preconcentration of ultra-trace levels of cadmium (ІІ) in different real samples followed by electrothermal atomic absorption spectrometry. Cerium oxide nanoparticles were synthesized by a microwave method and modified by polyaniline to produce polyaniline-coated cerium oxide nanoparticles. Fourier-transform infrared spectroscopy and scanning electron microscopy were used to characterize the synthesized adsorbent. To optimize the critical experimental conditions; surface response methodology—Box–Behnken experimental design was used. On the basis of the results, pH 8.4, 10 mg of polyaniline-coated cerium oxide nanoparticles, 14.4 min extraction time, and 4.3 min desorption time were selected as the optimum conditions. Under the optimum conditions the calibration curve of cadmium (ІІ) was linear in the range of 0.02–0.4 ng mL⁻¹ with a correlation coefficient of 0.9976. The relative standard deviation based on seven replicate analysis of 0.1 ng mL⁻¹ cadmium (ІІ) was 4.2% and limit of detection was 0.005 ng mL⁻¹ cadmium (ІІ). The analysis of certified reference material shows very good agreement with the certified value. Finally, the proposed method was applied for the determination of ultra-trace levels of cadmium (ІІ) in different water, rice, and tea samples.

Keywords:

• Box–Behnken optimization
• cerium oxide-coated polyaniline nanoparticles
• electrothermal atomic absorption spectrometry
• solid-phase extraction

Additional information

Funding

The authors thank the Ferdowsi University of Mashhad for the financial support of this project.