Using PVA/CA/Au NPs electrospun nanofibers as a green nanosorbent to preconcentrate and determine Pb2+ and Cu2+ in rice samples, water sources and cosmetics

Abstract

In the presented study, the synthesis of a nanosorbent for micro-solid phase extraction (μ-SPE) to extract and preconcentrate copper and lead from aqueous solutions was described. Au nanoparticles (Au NPs) were synthesized through a green method and used to synthesize the nanosorbent consisting of citric acid (CA) as a ligand and polyvinyl alcohol (PVA) as a helping polymer. PVA/CA/Au NPs electrospun nanofibers with a good extraction capacity and selectivity toward copper and lead were prepared in a single fluid solution and synthesized through an electrospinning strategy. Also, Au NPs were embedded and decorated in the nanofiber structure and the extraction efficiencies of the two kinds of sorbents were compared to each other. The characterization of NPs and nanosorbents was performed using ultraviolet-visible spectroscopy (UV-Vis), dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and element mapping images. Herein, the quantification of metals was carried out by flame atomic absorption spectroscopy (FAAS). To obtain the maximum extraction capability, the effective parameters on the extraction efficiency were surveyed and the optimal operation conditions were determined. At the optimal conditions, the method exhibited a good linearity range (2.0–100 ng mL⁻¹) with an R² higher than 0.997. The limit of detection (LOD) values for the method were in the range of 0.35–0.4 ng mL⁻¹ and the relative standard deviations (RSDs) were in the range of 3.1–4.7% (intra-day and inter-day). Finally, the method was applied to determine Pb²⁺ and Cu²⁺ in rice samples, water sources, and cosmetic samples using a non-toxic, inexpensive, and biodegradable sorbent.