Rapid Determination of Cadmium and Lead in Maca (Lepidium meyenii) by Magnetic Solid-Phase Extraction and Flame Atomic Absorption Spectrometry

Abstract

Multiwalled carbon nanotubes were modified by Fe₃O₄ nanoparticles with application for the preconcentration of metals. The modified materials were characterized by infrared spectroscopy, transmission electron microscopy, and X-ray diffraction. The Fe₃O₄ nanoparticle modified multiwalled carbon nanotubes were used as sorbents for the extraction of cadmium and lead from maca prior to analysis by flame atomic absorption spectrometry. The amount of nanoparticles, pH, adsorption time, coexisting ions, eluent solution, and reuse of the material were characterized to optimize the recoveries of the analytes. Under the optimum conditions, the calibration curves were linear from 0.05 to 20 milligrams per liter for cadmium and from 0.05 to 25 milligrams per liter for lead. The limits of detection were 0.32 and 0.57 micrograms per liter while the relative standard deviations were 2.1 and 1.9 percent, respectively. The method was employed for the determination of cadmium and lead in maca and recoveries between 94.8 and 105.6 percent were obtained.

Keywords::

• Cadmium
• Fe₃O₄ nanoparticles
• Flame atomic absorption spectrometry
• Lead
• Magnetic solid-phase extraction
• Multiwalled carbon nanotubes