Self-Assembled Three-Dimensional Microporous rGO/PNT/Fe3O4 Hydrogel Sorbent for Magnetic Preconcentration of Multi-Residue Insecticides

• Published in: Applied sciences 2020-08, Vol.10 (16), p.5665
• Main Authors: Wang, Sheng, Li, Xiuqin, Li, Ming, Li, Xianjiang, Li, Xiaomin, Li, Shuangqing, Zhang, Qinghe, Li, Hongmei
• Format: Article
• Language: English
• Subjects: Aqueous solutions; Carbamate pesticides; Carbamates (tradename); Carbaryl; Carbon; Chlorpyrifos; Chromatography; Cyhalothrin; Efficiency; Electrostatic properties; Gas chromatography; gas chromatography-tandem mass spectrometry; Graphene; Hydrogels; Hydrogen bonding; Hydrophobicity; Insecticides; Iron oxides; magnetic solid-phase extraction; Magnetite; Mass spectrometry; Mass spectroscopy; Methods; Mirex; Nanomaterials; Nanoparticles; Organochlorine compounds; Organophosphorus pesticides; Pesticides; Phorate; Phosalone; Pore size; Pore size distribution; Porosity; Porous materials; Pyrethroids; Quinalphos; Residues; Self-assembly; Size distribution; Solid phases; Solids; Sorbents; Stress concentration; Three dimensional analysis; Three dimensional composites; three-dimensional microporous composite; Tomatoes; Triazoles; Vegetables
• ISSN: 2076-3417; 2076-3417
• DOI: 10.3390/app10165665

The purpose of this work was to develop a highly selective, sensitive, and reliable method for multi-residual analysis. A three-dimensional microporous reduced graphene oxide/polypyrrole nanotube/magnetite hydrogel (3D-rGOPFH) composite was synthesized and utilized as a magnetic solid-phase extraction (MSPE) sorbent to preconcentrate thirteen insecticides, including five organophosphorus (isocarbophos, quinalphos, phorate, chlorpyrifos, and phosalone), two carbamates (pirimor and carbaryl), two triazoles (myclobutanil and diniconazole), two pyrethroids (lambda-cyhalothrin and bifenthrin), and two organochlorines (2, 4′-DDT and mirex), from vegetables, followed by gas chromatography-tandem mass spectrometry. This method exhibited several major advantages, including simultaneous enrichment of different types of insecticides, no matrix effect, high sensitivity, and ease of operation. This is ascribed to the beneficial effects of 3D-rGOPFH, including the large specific surface (237 m2 g−1), multiple adsorption interactions (hydrogen bonding, electrostatic, π–π stacking and hydrophobic interaction force), appropriate pore size distribution (1–10 nm), and the good paramagnetic property. Under the optimal conditions, the analytical figures of merit were obtained as: linear dynamic range of 0.1–100 ng g−1 with determination coefficients of 0.9975–0.9998; limit of detections of 0.006–0.03 ng g−1; and the intra-day and inter-day relative standard deviations were 2.8–7.1% and 3.5–8.8%, respectively. Recoveries were within the range of 79.2 to 109.4% for tomato, cucumber, and pakchoi samples at the fortification levels of 5, 25, and 50 ng g−1. This effective and robust method can be applied for determining multi-classes of insecticide residues in vegetables.