A sensitive method for the simultaneous analysis of vitamin A (VA), 25-hydroxyl vitamin D₃ (25-OH VD₃) and α-tocopherol (VE) in children plasma by liquid chromatography-tandem mass spectrometry (LC–MS/MS) has been developed and validated. Sample preparation chose the solid phase extraction. 100 μL of plasma was mixed with 300 μL ethanol contained 4 μL isotope-labelled analytes. After a series operation, the supernatant was applied to the solid phase extraction (SPE) plate (HLB μElution plate). The eluate was evaporated, and reconstituted in 100 μL methanol. And then, 6 μL reconstituted sample was injected into LC–MS/MS. Quantitative analysis was carried out by multiple reaction monitoring (MRM) with a positive mode electrospray (ESi + ). Separations of VA, 25-OH VD₃ and VE were performed on an Acquity UPLC reversed-phase Phenyl-Hexyl analytical column (CSH, 2.1 × 50 mm, 1.7 μm). Gradient elution was used at a flow rate of 0.4 mL/min with a mobile phase consisting of 0.1% formic acid solution and 0.1% formic acid, 5 mM ammonium formate in acetonitrile. The total time of analysis was 10 min. The method had a limit of quantification (LOQ) of 10.03, 1.20, and 0.04 ng/mL for VA, 25-OH VD₃ and VE in methanol, respectively. The linear calibration curves were fitted over the range of 0.14–14.32 μg/mL, 1.80–180.29 ng/mL, and 6.03–602.99 ng/mL for VA, 25-OH VD₃ and VE in methanol. The correlation coefficients were greater than 0.998 for all analytes. The recoveries for all analytes were between 80 and 120% with the inter- and intra-day precisions (presented as relative standard deviation, RSD%) less than 10.0%. Analysis of VA, 25-OH VD₃ and VE in recurrent respiratory tract infection children plasma and anemic infants’ fingertip blood was then carried out using this method and statistical analysis of the data with statistic package for social science 20.0 (SPSS 20.0). Using this method, multiple fat-soluble vitamins could be detected at the same time. Solid phase extraction was used to simplify sample pretreatment. μElution plate used here could reduce the sample volume, only 100 μL sample was used in this method, and 6 μL reconstituted sample was injected into LC–MS/MS. This makes the method appropriate for larger sample pretreatment, and suitable for children, especially infants and newborns’ sample detection, in whom the circulation blood was low.

液相色谱-串联质谱法（LC-MS / MS）同时分析儿童血浆中维生素A（VA），25-羟基维生素D ₃（25-OH VD ₃）和α-生育酚（VE）的灵敏方法）已开发并验证。样品制备选择了固相萃取。将100μL血浆与300μL乙醇混合，其中包含4μL同位素标记的分析物。经过一系列操作后，将上清液应用于固相萃取（SPE）板（HLBμElution板）。蒸发洗脱液，并在100μL甲醇中复溶。然后，将6μL重构样品注入LC-MS / MS中。通过正反应模式电喷雾（ESi +）的多反应监测（MRM）进行定量分析。VA，25-OH VD _3的分离和VE在Acquity UPLC反相苯基己基分析柱（CSH，2.1×50 mm，1.7μm）上进行。使用0.4 mL / min流速的梯度洗脱，流动相由0.1％甲酸溶液和0.1％甲酸，5 mM甲酸铵的乙腈溶液组成。分析的总时间为10分钟。对于甲醇中的VA，25-OH VD ₃和VE，该方法的定量限（LOQ）分别为10.03、1.20和0.04 ng / mL 。对于VA，25-OH VD ₃，线性校准曲线在0.14–14.32μg/ mL，1.80–180.29 ng / mL和6.03–602.99 ng / mL的范围内拟合和VE在甲醇中。所有分析物的相关系数均大于0.998。所有分析物的回收率在80％至120％之间，日间和日内精度（表示为相对标准偏差，RSD％）均小于10.0％。反复呼吸道感染儿童血浆和贫血中VA，25-OH VD ₃和VE的分析然后使用这种方法对婴儿进行指尖采血，并使用针对社会科学20.0（SPSS 20.0）的统计软件包对数据进行统计分析。使用这种方法，可以同时检测多种脂溶性维生素。固相萃取用于简化样品预处理。此处使用的洗脱板可以减少样品量，该方法仅使用100μL样品，并将6μL重构样品注入LC-MS / MS中。这使得该方法适合于较大的样品预处理，也适合于循环血液不足的儿童，尤其是婴儿和新生儿的样品检测。