A dispersive liquid-liquid microextraction (DLLME) method, combined with HPLC-UV detection, was developed for the extraction and preconcentration of δ-tocopherol from bovine milk. This method was used to study the effect of supplementing cow feed with the seaweed Ascophyllum nodosum on vitamin content in milk. The optimal experimental conditions were determined: 200 μL of chloroform (extraction solvent), 1.0 mL of ethanol (dispersive solvent), 5 mL of water (aqueous phase). Under these optimal conditions the DLLME method provided linearity in the range 0.01 μg/mL to 8 μg/mL with R² values of 0.998. Limit of detection (LOD) was 0.01 μg/mL, while the enrichment factor was 89. Cow feed that was supplemented with Ascophyllum nodosum was shown to increase δ-tocopherol levels from 3.82 μg/mL to 5.96 μg/mL.

建立了分散液-液微萃取（DLLME）方法与HPLC-UV检测相结合的方法，用于从牛乳中提取和预浓缩δ-生育酚。该方法用于研究向牛饲料中添加海藻Ascophyllum nodosum对牛奶中维生素含量的影响。确定了最佳实验条件：200μL氯仿（萃取溶剂），1.0 mL乙醇（分散溶剂），5 mL水（水相）。在这些最佳条件下，DLLME方法提供的线性范围为0.01μg/ mL至8μg/ mL，R ²值为0.998。检测极限（LOD）为0.01微克/毫升，而富集因子是补充有89奶牛饲料泡叶藻 结果显示δ-生育酚水平从3.82μg/ mL增加到5.96μg/ mL。