Synthesis and Characterization of Modified Multiwall Carbon Nanotubes With Poly (N-Phenylethanolamine) and Their Application for Removal and Trace Detection of Lead Ions in Food and Environmental Samples

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This paper describes, a new, sensitive, and low-cost solid-phase extraction method using poly (N-phenylethanolamine)/multiwalled carbon nanotube (MWCNT) nanocomposite for extraction, preconcentration, and flame atomic absorption spectrometric determination of lead in food and water samples at trace levels. The poly (N-phenylethanolamine)/MWCNT nanocomposites were characterized by Fourier transformed infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), Brunauer-Emmett-Teller (BET) surface area (SBET), and scanning electron microscopy (SEM). Factors affecting the preconcentration of lead such as the pH of samples, flow rates, type and volume of eluent, and the effect of interfering ions and breakthrough volume on the separation and determination of lead ions were investigated. The optimum conditions for the adsorption step were 5.0 and 18 mL min−1 for pH and sample flow rate, respectively, and for desorption step, the optimal condition were 1.5 mL, 1 mol L−1 HCl, and 2 mL min−1, for volume of eluent, concentration of eluent, and eluent flow rate, respectively. The maximum sorbent capacity of the poly (N-phenylethanolamine)/MWCNT nanocomposite was calculated to be 152.1 mg g−1. The preconcentration factor, relative standard deviation, and limit of detection of the method were found to be 100, 3.1 % (10.0 μg L−1, n = 5), and 0.8 μg L−1, respectively. The presented method was validated by certified reference material (NIST SRM 1515 Apple leaves and IAEA-336 Lichen) and finally applied to analysis of lead ions in food (Citrus limetta, kiwi, pomegranate, and fish samples) samples. The obtained data for analysis of lead ions in food samples were in the concentration range of 4.1–50.8 μg kg−1.