Dispersive liquid-liquid microextraction coupled with magnetic nanoparticles for extraction of zearalenone in wheat samples

A new, sensitive and fast dispersive liquid-liquid microextraction (DLLME) coupled with micro-solid phase extraction (μ-SPE) was developed for determination of zearalenone (ZEN) in wheat samples. The DLLME was performed using acetonitrile/water (80:20 v/v) as the disperser solvent and 1-octanol as the extracting solvent.  The acetonitrile/water (80:20 v/v) solvent was also used to extract ZEN from solid wheat matrix, and was directly applied as the disperser solvent for DLLME process. Additionally, hydrophobic oleic-acid-modified magnetic nanoparticles were used in μ-SPE approach to retrieve the analyte from the DLLME step. So, the method uses high surface area and strong magnetism properties of these nanoparticles to avoid time-consuming column-passing processes in traditional SPE. Main parameters affecting the extraction efficiency and signal enhancement were investigated and optimized. Under the optimum conditions, the calibration curve showed a good linearity in the range of 0.1-500 μg kg−1 (R2=0.9996) with low detection limit of 83 ng g−1. The intra-day and inter-day precisions (as RSD %) in the range of 2.6-4.3 % and high recoveries ranging from 91.6 to 99.1 % were obtained. The pre-concentration factor was 3. The method is simple, inexpensive, accurate and remarkably free from interference effects.