Rapid detection of three pesticide residues in vegetables based on magnetic solid phase extraction and portable ion trap mass spectrometer

A rapid method was established for the detection of acetamiprid, imidacloprid and carbofuran in three typically high residue vegetables, including celery, leek and cowpea, using magnetic solid-phase extraction and portable ion trap mass spectrometer. The main extraction conditions were optimized and the suitable procedures were as follows: The vegetable samples were extracted by 20 mL water, and the target pesticides in the extracted solution was then adsorbed by 30 mg magnetic solid-phase absorbents using the ultrasonic extraction for 15 min. After the magnetic separation, the adsorbed pesticides were desorbed with 4 mL of acetonitrile with 0.1% (V/V) formic acid by ultrasonic extraction for 3 min. Method validation indicated that all the three pesticides showed good linearity in the range of 0.01-0.25 mg/L, except that it was 0.05-0.5 mg/L for imidacloprid in leek sample. The limits of detection were 0.001-0.035 mg/L, and the limits of quantitation were 0.02-0.05 mg/kg. The spiked recoveries ranged from 50% to 71% with the RSDs of 4.2% to 22% at the spiked levels of 0.02, 0.05 and 0.2 mg/kg. The presented method displayed good qualitative/semi quantitative ability, and could be used for simultaneous and rapid on-site detection of multiple pesticide residues in vegetables.