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Abstract
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In this research, a solid-phase extraction (SPE) method based on application of cobalt
oxide nanoparticles (Co3O4 NPs) as a novel nano-sorbent was developed for preconcentration
and extraction of zinc(II) ions from various real samples followed by flame atomic absorption
spectrometric (FAAS) detection. Co3O4 NPs were simply synthesized via a thermal treatment of
cobalt hydroxide after a precipitation method, and its structure and morphological properties
were studied by Fourier transform infrared spectrometry, X-ray diffraction, and scanning
electron microscopy. The effect of various parameters influencing the extraction recovery of
Zn(II) ion such as extraction time, pH, amount of the nano-sorbent, sample volume and elution
conditions were studied and optimized. Applying optimum conditions for SPE procedure, the
limit of detection was 0.25 ng mL‒1 and the calibration graph was linear in the concentration
range of 0.4‒32 ng mL‒1 with a correlation coefficient of 0.9951. The method intra- and interday
precisions, calculated by performing five replicates at the concentration level of 20 ng
mL‒1
, were obtained 2.3% and 2.6%, respectively. The applicability of the developed SPEFAAS
method was evaluated by its application for measuring zinc concentration in various
samples including tap water, river water, well water, milk and powder milk samples, and the
relative recoveries were obtained in the range of 94.5‒103.5% for the spiked samples
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