A Novel Method of Homogeneous Liquid–Liquid Microextraction via Flotation Assistance Coupled to Liquid Chromatography for the Determination of Trace Imidacloprid in Water Samples

This paper describes a novel method for the sensitive determination of imidacloprid using homogeneous liquid−liquid microextraction via flotation assistance (HLLME-FA) in water samples. After the extraction procedure, low density organic solvent was separated by air flotation. Various parameters affecting the extraction efficiencies such as the types of extraction and homogeneous solvents, the volumes of extraction and homogeneous solvents, extraction time and ionic strength were studied. Under the optimized conditions, the detection limit of imidacloprid was 0.02 µg/L. The experimental results indicated that there was good linearity (r2 = 0.9995) over the range of 0.25–500 µg/L. The relative standard deviation (n = 3) at the concentration level of 1.0 µg/L of imidacloprid in sea, well and river water samples was 11.1%. The proposed method has been successfully applied to the determination of imidacloprid in real water samples.