Microwave-Assisted Preparation of Zirconium Intercalated Expanded Graphite for Chlorpyrifos Determination in Honey

Herein, we proposed a simple and efficient microwave-assisted preparation method for the fabrication of zirconium (IV) intercalated expanded graphite (Zr-EG). The synthetic approach could be completed in one step within 20 s, where KMnO4 was used as the oxidizing agent, H2SO4 and ZrOCl2 as the intercalating agents. The as-prepared Zr-EG exhibited thin multi-layered structure, plenty of small Zr-relevant particles and oxygenated groups in both layers and surface, which gave Zr-EG high absorption capability. Subsequently, the Zr-EG, as a new kind of solid-phase extraction absorbent, was applied to the separation, purification and enrichment of chlorpyrifos in honey samples, followed by high-performance liquid chromatography analysis. Under optimal extraction and analysis conditions, the detection limit was 100 ng g−1. The relative standard deviations ranged from 2.6 to 6.8%. At three spiked levels (1, 10, 100 μg g−1), the recoveries of chlorpyrifos were in the range of 86.1–92.2%. Comparison with other conventional solid-phase extraction adsorbents, modified EG showed rapid synthesis, layered modification flexibility, stable structure, large adsorption capacity and good selectivity, demonstrating great potential in pollutants separation and detection.