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建立了在线二维液相色谱同时快速测定婴幼儿配方乳品和成人强化乳品中维生素 A、D3和 E 含量的方法。首先，依据疏水减法模型，选择 C8柱和极性嵌合的反相 C18柱分别作为一维和二维分离柱，构成正交分离体系，并均以甲醇、乙腈和水作为流动相，检测波长设为263 nm（维生素D3）、296 nm（维生素E）和325 nm（维生素A）。采用双三元液相色谱的左泵作为一维分析泵，完成维生素 A、E的定量和维生素 D3的净化；根据维生素 D3在一维色谱柱上的保留时间，确定切割时间窗口，并以500μL定量环收集含有维生素 D3的馏分，由双三元液相色谱的右泵将馏分带到二维色谱柱中，以维生素 D2作为内标物，采用内标法完成维生素 D3的定量分析，整个过程在密闭系统中自动化完成。在上述优化条件下测定了婴幼儿和成人奶粉、奶酪及酸奶等强化乳品中3种维生素的含量。经过1.25 kg／L KOH溶液的热皂化和石油醚的萃取，样品萃取液直接进样分析，得到维生素D3的加标回收率为75．50％~85．00％，并通过配对 t检验法与标准方法测定结果进行比较分析，结果差异无统计学意义，表明本方法可同时快速、准确测定婴幼儿及其他配方营养品中维生素 A、D3、E的含量，提高了样品分析效率。

A rapid method for the simultaneous determination of vitamins A,D3 and E in infant formula and adult nutritions has been developed using online two-dimensional liquid chromatog-raphy(2D-LC). First of all,C8 and polar embedded C18 columns were chosen as the first and second dimensional column respectively according to hydrophobic-subtraction model,which constituted excellent orthogonal separation system. The detection wavelengths were set at 263 nm for vitamin D3,296 nm for vitamin E and 325 nm for vitamin A. The purification of vitamin D3 and quantifications of vitamins A and E were completed simultaneously in the first dimen-sional separation using the left pump of Dual Gradient LC( DGLC)with methanol,acetonitrile and water as mobile phases. The heart-cutting time window of vitamin D 3 was confirmed according to the retention time of vitamin D 3 in the first dimensional separation. The elute from the first dimensional column( 1-D column)which contained vitamin D 3 was collected by a 500μL sample loop and then taken into the second dimensional column( 2-D column)by the right pump of DGLC with methanol,acetonitrile and water as mobile phases. The quantification of vitamin D3 was performed in the second dimensional separation with vitamin D 2 as internal standard. At last,this method was applied for the analysis of the three vitamins in milk pow-der,cheese and yogurt. The injected sample solution with no further purification was pre-trea-ted by hot-saponification using 1. 25 kg/L KOH solution and extracted by petroleum ether sol-vent. The recoveries of vitamin D3 spiked in all samples were 75.50%—85.00%. There was no sta-tistically significant difference for the results between this method and standard method through t-test. The results indicate that vitamins A,D3 and E in infant formula and adult fortified dairy can be determined rapidly and accurately with this method.