Chitosan-Cross Linked Polyaniline Reinforced Graphene Nanocomposite as a Highly Efficient Extractor of Polycyclic Aromatic Hydrocarbons (Pahs) from Black and Green Tea Samples

Abstract

Tea is one of the most popular drinks in the world because of its antioxidant, antibacterial, antiviral, and anticarcinogenic effects. Tea leaves may accumulate residues of polycyclic aromatic hydrocarbons (PAHs) as a result of production process and environmental pollutants, which may then be transmitted to tea infusions and provide a certain level of drinking safety. Herein, a micro-solid phase extraction method (MSPE) based on graphene reinforced with chitosan/polyaniline nanocomposite (CS/PANI/G) was applied for the preconcentration/extraction of seven PAHs from tea infusions, followed by high-performance liquid chromatography-fluorescence detection. The extraction mechanism contributes to increasing the hydrophobic cation- π and π-π interactions between the PAHs and the CS/PANI/G surfaces. When the target PAHs (benzo[a]pyrene, benzo[a]anthracene, benzo[b]fluoranthene, chrysene, benzo[b]fluoranthene, dibenzo[a,h] anthracene, and benzo[g,h,i] perylene) were assayed in black and green tea samples, excellent recoveries were observed, ranging from 88.0 to 112.1%. Under ideal circumstances, the relative standard deviations (RSD) for the seven PAHs were less than 4.0%, and the LOD, LOQ, and linear ranges were each achieved at 0.073-0.480, 0.881-1.455, and 0.50-100 µg kg-1, respectively. The high specific surface area of porous graphene and the excellent molecular structure recognition and enriching capabilities of CS and PANI constitute additional advantages of the proposed technique.

Keywords: Chitosan, Polyaniline, polycyclic aromatic hydrocarbons (PAHs), graphene, Adsorption, Green and Black Tea