Application of Polydopamine-Based Magnetic Solid-Phase Extraction for Highly Sensitive Determination of Aristolochic Acid I from Traditional Chinese Medicine Samples

Abstract A low cost-effective and simple synthesis method combining magnetic solid-phase extraction (MSPE) and high-pressure liquid chromatography was developed for the analysis of aristolochic acids I (AAI) in traditional Chinese medicine samples. A novel polydopamine (PDA) modified magnetic nanoparticles with one single carbon layer (Fe3O4@1C NPs) via one-pot hydrothermal approach was prepared and then successfully employed to extract AAI for the first time. Dopamine (DA) can form a PDA layer on Fe3O4@1C NPs surface through self-polymerization to form Fe3O4@1C@PDA. As a surface modifier of DA, PDA offered more adsorption sites to AAI due to π–π stacking, hydrogen bonding and electrostatic interactions. The parameters of MSPE were optimized by univariate and multivariate methods (Box–Behnken design) in detail. High degree of linearity was obtained in the range of 0.05–200.0 μg/mL. The limits of detection (S/N = 3) and quantification (S/N = 10) were 0.08 and 0.25 μg/mL, respectively. The recoveries of AAI in spiked Xiaoqinglong mixture samples were in the range of 86.7 to 108.5% with the relative standard deviation of less than 5.2%. Thus, a fast, convenient, sensitive and eco-friendly method was successfully proposed and became a promising approach for the determination of AAI in herbal plants or its preparation in the manufacturing procedure.