Determination of five pyrethroids in tea drinks by dispersive solid phase extraction with polyaniline-coated magnetic particles

The polyaniline-coated magnetic particles with bowl-shaped morphology (Fe 3 O 4 /C/PANI microbowls) were successfully prepared and characterized by scanning electron microscopy, transmission electron microscopy and vibrating sample magnetometry . The prepared microbowls were used as the magnetic adsorbent in dispersive solid phase extraction of five pyrethroids , including cyhalothrin , beta-cypermethrin, esfenvalerate , permethrin and bifenthrin in plain tea drinks. The effects of experiment factors, including amount of Fe 3 O 4 /C/PANI microbowls, pH value, ultrasound extraction time and desorption conditions, were investigated. The extraction recoveries obtained with 8   mg of magnetic microbowls were satisfactory, and the microbowls can be reused after easy washing. Thus, a simple, selective and effective method for the determination of the pyrethroids was established successfully. The results showed that the method had good linearity ( r =0.9992–0.9998), and the limits of detections (LODs) were from 0.025 to 0.032   ng   mL −1 . The intra-day and inter-day relative standard deviations (RSDs) were in the range of 2.4–6.1% and 3.5–8.8%, respectively. Recoveries obtained by analyzing the real tea drinks were in the range of 72.1–118.4%.