Turner C, Mathiasson L
Department of Analytical Chemistry, Lund University, Sweden.
J Chromatogr A. 2000 Apr 7;874(2):275-83. doi: 10.1016/s0021-9673(00)00096-0.
A method for the analysis of the natural contents of vitamins A and E in milk powder has been developed. The method utilises supercritical fluid extraction, a miniaturised alkaline saponification procedure and reversed-phase HPLC with UV detection. Modifications of the sample matrix, combinations of static and dynamic modes of extraction and effects of changes in extraction parameters such as temperature, flow-rate, time, collection solvent and collection temperature were studied to optimise the extraction efficiency and selectivity. Supercritical CO2 at 80 degrees C and 37 MPa, modified with 5% methanol and pumped at a flow-rate of 1.0 ml/min, gave recoveries of 99 and 96% for vitamins A and E, respectively, using a 15 min static followed by a 15 min dynamic extraction. The measurements gave a within-day RSD of 4% for both vitamin A and E, and between-day RSDs of 4 and 8% for vitamins A and E, respectively.
已开发出一种分析奶粉中维生素A和维生素E天然含量的方法。该方法采用超临界流体萃取、小型化碱性皂化程序以及带紫外检测的反相高效液相色谱法。研究了样品基质的改性、静态和动态萃取模式的组合以及萃取参数（如温度、流速、时间、收集溶剂和收集温度）变化的影响，以优化萃取效率和选择性。在80℃和37MPa下，用5%甲醇改性的超临界CO2以1.0ml/min的流速泵送，采用15分钟静态萃取后再进行15分钟动态萃取，维生素A和维生素E的回收率分别为99%和96%。测量结果表明，维生素A和维生素E的日内相对标准偏差均为4%，维生素A和维生素E的日间相对标准偏差分别为4%和8%。
