高效液相色谱法测定食品中大豆异黄酮

目的：建立高效液相色谱法测定食品中大豆异黄酮（包括染料木黄酮和大豆苷元）的含量，探讨样品的提取方法及测定影响因素。方法：样品经0.50mol/L盐酸回液和乙醇提取大豆异黄酮后，采用甲醇－0.01mol/L乙酸铵溶液（pH4.5)(60 40)作为流动相分离待测物质，等度洗脱，采用紫外检测器于254nm波长下测定。结果：染料木黄酮的检出限为0．04μg/ml，大豆苷元为0．05μg/ml，样品的加标回收率为91．4％－113．1％，日内和日间相对标准偏差分别为1．1％－2．8％和2．9％－5．1％。结论：本法简便、快速，易于推广普及，为大豆及其制品和保健食品中大豆异黄酮的检测和膳食摄取植物性雌激素提供了分析方法。

Determination of Soybean Isoflavones in Foods by HPLC

OBJECTIVE: To establish a method for the determination of soybean isoflavones including daidzein and genistein in foods by high performance liquid chromatography. METHODS: Soybean isoflavones in food samples were refluxed and extracted by 0.5 mol/L hydrochloric acid and ethanol. Soybean isoflavones were chromatographically separated on a C18 column with a mobile phase consisting of methanol and 0.01 mol/L ammonium acetate buffer solution (pH 4.5) (60 + 40), and then detected at 254 nm with ultraviolet-visible detector. RESULTS: The detection limits were 0.05 microg/ml for daidzein and 0.04 microg/ml for genistein, respectively. The spiked recoveries of the samples were 91.4%-113.1%. The within-day and between-day (n = 6) relative standard deviations were 1.1%-2.8% and 2.9%-5.1%, respectively. CONCLUSION: The method is simple, sensitive and applicable to the determination of soybean isoflavones in foods. It also provides an analytical method for isoflavones in functional food and the absorption of phytoextrogens from foods.