Nonanoic acid-coated magnetite nanoparticles for separation and preconcentration of lead and copper in tobacco samples prior to flame atomic absorption spectrometry determination

Abstract

A new method using nonanoic acid-coated magnetic Fe3O4 nanoparticles as adsorbent has been developed for the single-step extraction and preconcentration of lead and copper in tobacco samples. Transmission electron microscopy and X-ray diffraction spectrometry were used to characterize the adsorbent. The experimental parameters affecting extraction efficiency, including amount of nanoparticles, volume of chelating reagents, sample pH, ultrasonic time and desorption conditions were investigated. The analytes desorbed from nanoparticles were determined by flame atomic absorption spectrometry. Under the optimum conditions, good linearity was obtained in the range of 2-400 ?g L-1 for copper and 5-800 ?g L-1 for lead (r > 0.998, p < 0.05). The limits of detection for copper and lead were 0.2 and 0.5 ?g L-1, with enrichment factors of 45 and 52, respectively. The method was successfully employed to tobacco sample analysis and got excellent recoveries between 89.2 and 100.7% with relative standard deviations (n = 6) of 4.5-5.9%.