Determination of 3 neonicotinoid pesticide residues in paddy field with high performance liquid chromatography

A method of determining dinotefuran, imidacloprid and acetamiprid in paddy water, paddy soil, rice plant, rice stem, hull and brown rice was established by high performance liquid chromatography with ultraviolet detector. The samples of paddy water, paddy soil, rice plant, rice stem, and hull were extracted with acetonitrile, and rice samples were extracted with mixture of acetonitrile and water(1:1, V/V). Samples were cleaned up with Florisil columns except paddy water, and determined by high performance liquid chromatography with ultraviolet detector. Methanol and water (30:70, V/V) was used as mobile phase at a gradient flow rate, and ultraviolet absorption wavelength was set at 254 nm. It was shown that the calibrations were linear, and the equation and the determination coefficient (R2) was as followed: dinotefuran: y=62.55x+4.039 2(R2=0.999 2); imidacloprid: y=99.968x+7.525 1(R2=0.998 6); acetamiprid: y=97.084x+6.072(R2=0.999 4). The average recoveries of samples ranged from 81% to 99% at spiked levels of 0.05-2 mg/kg, and relative standard deviation (RSD, n=5) was in the range of 1.2%-7.9%. Pre-treatment process of the method was simple, and the sensitivity and accuracy of the method met with the technical requirements for pesticide residue analysis.