Determination of Pyrethroids in Paris polyphylla Sample by High-Performance Liquid Chromatography Using Ultrasound-Assisted Magnetic Solid-Phase Extraction

Figure 5

Effect of the amount of MNPs. Extraction conditions: sample volume, 50.0 mL spiked with 100 ng mL⁻¹ of four pyrethroids; pH, 7.0; ultrasonication time, 2 min; eluent solvent, 2 mL of acetonitrile/acetic acid (9:1, v/v).