Abstract

A rapid and easy sample pretreatment procedure, matrix acidity-induced switchable hydrophilicity solvent-based homogeneous liquid-liquid microextraction, has been developed for the isolation of the synthetic antioxidants butylated hydroxyanisole and butylated hydroxytoluene from vinegar samples. Di-(2-ethylhexyl)phosphoric acid (DEHPA) was selected as the extraction solvent and its hydrophilic form was obtained in alkaline solution followed by the addition of vinegar, which acted as both the sample and the inductor of the switching reaction leading to the formation of DEHPA microdroplets. There was no need to centrifuge at this step, since the DEHPA phase containing the analytes was collected from the resulting mixture through magnetic retrieval due to its high affinity for Fe₃O₄ nanoparticles. After being magnetically separated, the desorbed analytes were analyzed by high performance liquid chromatography with ultraviolet detection (HPLC-UV). Under the optimized conditions, the limits of detection for the analytes were between 3.2 and 5.5 µg L⁻¹ and the linear dynamic range was from 10 to 500 μg L⁻¹. Good precision was obtained with relative standard deviations less than 7.8%. Recovery assays for spiked apple, grape, and white vinegar provided recoveries from 86 to 105%.

摘要

已经开发了一种快速简便的样品预处理程序，即基质酸度诱导的可切换亲水性溶剂型均相液-液微萃取，用于从醋样品中分离合成抗氧化剂丁基化羟基苯甲醚和丁基化羟基甲苯。选择二-(2-乙基己基)磷酸 (DEHPA) 作为萃取溶剂，在碱性溶液中得到其亲水形式，然后加入醋，醋作为样品和开关反应的感应器，导致DEHPA 微滴的形成。在这一步不需要离心，因为含有分析物的 DEHPA 相是通过磁回收从所得混合物中收集的，因为它对 Fe ₃ O _{4具有高亲和力}纳米粒子。经磁分离后，解吸的分析物通过带紫外检测的高效液相色谱法（HPLC-UV）进行分析。在优化条件下，分析物的检测限在 3.2 到 5.5 µg L ^-1之间，线性动态范围在 10 到 500 µg L ^-1之间。获得了良好的精密度，相对标准偏差小于 7.8%。加标苹果、葡萄和白醋的回收率测定提供了 86% 至 105% 的回收率。