Determination of Eugenol Residue in Aquatic Using Dispersive Liquid-Liquid Microextraction Based on the Solidification of a Floating Organic Droplet Followed by UHPLC-MS/MS

A novel dispersive liquid-liquid microextraction based on solidification of floating organic droplet (DLLME-SFO) followed by ultra performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) was developed for the determination of eugenol residue in aquatic. The influence of extraction parameters including types of extraction solvent, volume of extraction solvent, vortex extraction time, sodium chloride mass fraction, chromatographic condition and mass spectrometry condition were investigated. The optimal liquid-liquid microextraction experiment conditions were as follows: 30 μL 1-undecanol as extraction solvent, 800 μL of methanol as disersive solvent, sodium chloride mass fraction 6%, vortex oscillation extrantion time 3 min, centrifugal time was 5 min with 10 000 r/min at three degrees below zero centigrade, dislodge water phase, after thawed it was analyzed by UHPLC-MS/MS. The analytical column was DIKMA Endeavorsil C18（30 mm×2.1 mm×1.8 μm）, and the mobile phase was composed of methanol-water solution (80∶20,V/V). The flow rate was 0.30 mL/min and run time was 2.0 min. A tandem mass spectrometer coupled with negative electro-spray ionization (ESI) source was used for detection. The quantitative detection was performed on UHPLC-MS/MS by multiple reaction monitoring (MRM) mode under negative electro spray ionization (ESI^-). It was shown that good linearity is obtained at the concentrations of 5.0-500.0 μg/kg with the correaltion coefficients higher than 0.999 6 for eugenol. The recovery is 88.9%-103.4%. The limits of detection (LOD) and limit of quantification (LOQ) for eugenol are 1.47 μg/kg and 4.91 μg/kg, respectively. The intra-day relative standard deviations are lower than 7.5%（n=6）, and the inter-day relative standard deviations are lower than 9.8%（n=3）. MRL of eugenol in aquatic product was not demanded in China. Therefore, analytical of eugenol content in different aquatic products is of considerable importance and requires the development of precise methods for its determination imperatively. The method is efficient, solvent saving, reliable and sensitive, and can be suitable for the determination of eugenol residue in aquatic.