食品中微量維生素A檢驗方法探討

STUDY ON THE ANALYTICAL METHOD OF VITAMIN A IN FOOD

中國國家標準 CNS8859 N6168-食品中維生素A含量測定法，即是採用A.O.A.C.1984版所載之 Carr-price 方法加以簡化而得到。Carr-Price 法是利用維生素A氯仿溶波與三氯化銻反應會呈藍色反應，經分光光度計於波長620nm 測其吸光值，再加以換算維生素A之含量。但此法之藍色反應消退極快，回收率低且不穩定，另外其所使用之試藥具腐蝕性、毒性。鑑於此法之缺失，改採用高效液相層析法定量檢測之。經添加不同量之標準品至嬰兒配方食品，特殊營養健康食品及一般食品作一系列回收試驗後發現，回收結果良好，回收率均達90%以上，且其標準偏差（Std. Dev.） 均在1.14～7.64%間，變異係數（CV）在1.19～7.32%間，故顯示此改良後之方法具良好的穩定性及精確性。

Chinese National Standard Analytical Method (CNS 8859 N 6168) was modified from Carr-Price Method. In Carr-Price Method, Vitamin A-CHCl3 solution reacts with SbCl3 solution and shows a blue color, then the absorbance at 620nm is measured with a spectrophotometer. But the blue color of Carr-Price method disappears very soon and is hard to measure. The recoveries are low and not stable. Furthermore, the chemical reagents are caustic and toxic to human. To improve the analytical method, a High Performance Liquid Chromatographic method was developed for quantitative analysis of Vitamin A. Separation was achieved by using µ-Bondapak C18 column with mobile phase of methanol:H2O (95:5) at a flow rate of 1.0 ml/min. Different amounts of standard were added to Infant formula, health food, or general food to make a series of recovery analyses. The results showed that recoveries were good (higher than 90%), and the standard devision values were between 1.14 and 7. 64%, while the cofficients of variation were between 1.19 and 7.32%.