In this study, novel carbon quantum dots/oleic acid-coated Fe₃O₄ composites (Fe₃O₄-OA/CQDs) were successfully synthesized via a simple synthesis strategy and used to prepare the ferrofluid for the extraction and determination of phenolic compounds from water and pretreated milk samples followed by HPLC. The ferrofluid was composed of ionic liquids (ILs) and Fe₃O₄-OA/CQDs. With the introduction of CQDs, the ferrofluid showed good dispersing capability in aqueous samples, and the method exhibited lower relative standard deviations (RSDs) (1.1–2.1%), which indicated its good reproducibility. In addition, a proper carbon chain length for ILs might maintain the integrity of the ferrofluid during the extraction process and increase the extraction efficiency of the method. Under the optimum conditions, the limits of detection were in the range of 0.09–0.17 μg L⁻¹. And the intra-day and inter-day precision (RSD%) for the analytes at 20 and 100 μg L⁻¹ were in the range of 1.5–2.6% and 1.6–2.8%, respectively. The recoveries of bisphenols and 4-tert-octylphenol in water and milk samples were between 94.5 and 102.1%, and the RSDs were all in range of 1.7 to 4.1%.

在这项研究中，通过简单的合成策略成功合成了新型碳量子点/油酸包覆的Fe ₃ O ₄复合材料（Fe ₃ O ₄ -OA / CQDs），并用于制备铁磁流体，用于萃取和测定酚类化合物从水和预处理的牛奶样品中提取，然后进行HPLC。铁磁流体由离子液体（ILs）和Fe ₃ O _4组成-OA / CQD。随着CQD的引入，铁磁流体在水性样品中显示出良好的分散能力，并且该方法显示出较低的相对标准偏差（RSD）（1.1–2.1％），表明其具有良好的重现性。此外，IL的合适碳链长度可能会在萃取过程中保持铁磁流体的完整性，并提高该方法的萃取效率。在最佳条件下，检出限在0.09–0.17μgL ^-1范围内。并且在20和100μgL ^-1时分析物的日内和日间精度（RSD％）分别在1.5–2.6％和1.6–2.8％的范围内。水和牛奶样品中双酚和4-叔辛基苯酚的回收率在94.5至102.1％之间，RSD均在1.7至4.1％的范围内。