Air-assisted liquid-liquid micro-extraction based on the solidification of a floating organic droplet for the determination of three strobilurin fungicides in water samples

Abstract

ABSTRACT A simple, fast, air-assisted liquid-liquid micro-extraction technique using the solidification of a floating organic droplet method was developed for the extraction of three strobilurin fungicides in water samples before analysis by high-performance liquid chromatography equipped with a diode array detector (HPLC-DAD). In this method, a low-density solvent (1-dodecanol) was used as the extraction solvent. Fine extraction solvent droplets were rapidly formed and dispersed into the water samples through air-pumping by syringe rather than an organic disperser solvent. The extractant droplets with its freezing point near room temperature could be gathered from the top of the water sample after solidification in anice bath. Under optimal extraction conditions (200 μL of 1-dodecanol, four extraction cycles, 150 mg of NaCl), good linearities were obtained with correlation coefficients exceeding 0.996 and the limits of detection varied between 0.73 and 8.49 ng mL−1. The practical applicability of the proposed method was verified by the determination of three strobilurin fungicide contents in tap water, river water, well water and seawater. Extraction recoveries were between 75.3% and 98.3% with relative standard deviations ranging from 1.2% to 8.5%.The results prove that the method has promising applications for low-cost, accurate and rapid determination of strobilurin fungicides in water samples.