A novel dispersive liquid-liquid microextraction method based on amine-functionalized Fe3O4 magnetic nanoparticles was developed for the determination of six phenolic acids in vegetable oils by high-performance liquid chromatography. Amine-functionalized Fe3O4 was synthesized by a one-pot solvothermal reaction between Fe3O4 and 1,6-hexanediamine and characterized by transmission electron microscopy and Fourier transform infrared spectrophotometry. A trace amount of phosphate buffer solution (extractant) was adsorbed on bare Fe3O4-NH2 nanoparticles by hydrophilic interaction to form the "magnetic extractant". Rapid extraction could be achieved while the "magnetic extractant" on amine-functionalized Fe3O4 nanoparticles was dispersed in the sample solution by vortexing. After extraction, the "magnetic extractant" was collected by application of an external magnet. Some important parameters, such as pH and volume of extraction and desorption solvents, the extraction and desorption time needed were carefully investigated and optimized to achieve the best extraction efficiency. Under the optimal conditions, satisfactory extraction recoveries were obtained for the six phenolic acids in the range of 84.2-106.3%. Relative standard deviations for intra- and inter-day precisions were less than 6.3 and 10.0%, respectively. Finally, the established method was successfully applied for the determination of six phenolic acids in eight kinds of vegetable oils.

Based on the phenomenon that the acetonitrile-water system can form phase separation in the presence of sugar, a sugaring-out assisted liquid=liquid extraction coupled with HPLC protocol was proposed for the determination of honokiol and magnolol in traditional Chinese herbal formula Huoxiang-Zhengqi oral liquid. Extraction conditions such as the type and concentration of sugaring-out agent, the volume of acetonitrile, pH value, temperature, and vortex time were investigated. Separation was performed on a Diamonsil C 18 column (150 Â 4.6 mm i.d., 5 mM) with acetonitrile and 0.05% formic acid (60:40, v=v) as mobile phase. The column effluents were monitored at 254 nm. The method showed good linearity for honokiol and magnolol in the range of 0.5-50.0 mg Á mL À1 , and the limits of detection were 13 and 24 ng Á mL À1 , respectively. RSD values for repeatability and reproducibility were less than 1.62% and 1.80%, respectively. The recoveries were in the range of 85.8-103.7%. Compared with the Chinese Pharmacopoeia method, the established method was simple, fast, and greatly reduced the consumption of toxic organic solvent. Statistical test showed that the analytical results for the determination of the same sample by the two methods had no significant difference.