Determination of 3 neonicotinoid insecticides, nitenpyram, imidacloprid, and acetamiprid, was studied.
Vegetables and fruits were extracted with acetonitrile. The crude extract was passed through a weak
anion-exchange cartridge (PSA). The effluent was subjected to silica gel cartridge. Imidacloprid and
acetamiprid were eluted with 10 mL of 4:6 (v/v) acetone/hexane, followed by nitenpyram with acetone
(20 mL). Pesticides were determined by HPLC with a C-18 column and diode-array detection system.
Imidacloprid and acetamiprid were recovered at about 90% at the spike levels with 0.2 and 2 mg/kg
in cucumber, potato, tomato, eggplant, Japanese radish, and grape. Nitenpyram was recovered at
64-80%. Relative standard deviations were less than 10% throughout all the recovery tests. In the
residue analysis, agriculturally incurred pesticides at 0.08-0.14 mg/kg were designated with UV
spectra compared with respective reference standards.