Ultrasound-assisted emulsification magnetic microextraction: a fast and green method for the determination of triazole fungicides in fruit juice

A fast microextraction technique, termed as ultrasound-assisted emulsification magnetic microextraction, was developed for the determination of triazole fungicides (penconazole, tebuconazole and myclobutanil) in fruit juice samples by gas chromatography flame ionization detection. The distinct advantage of the proposed method is that a low toxic solvent, 1-octanol, is used as an extractant, without using a disperser. With the help of ultrasound, emulsification can be obtained. Magnetic nanoparticles are applied to retrieve the extractant, replacing centrifugation. Under optimal conditions, good linearity in the range of 5 μg L−1 to 500 μg L−1, repeatability (RSD 3.5–7.7%), low LODs (1.8–2.3 μg L−1) and good recovery (85.4–105%) were obtained. Additionally, the intermolecular binding energies were theoretically studied using density functional theory and the explicit solvent molecule model. A high correlation was found among the extraction efficiency, Kow and the calculated energies, which may guide the application of extractants and the selectivity of the target analytes in analytical methods.