Chengdu Institute of Biology, Chinese Academy of Sciences, No 9, Section 4, Renmin Nan Road, Chengdu, Sichuan, People's Republic of China.
J Agric Food Chem. 2013 Aug 28;61(34):8072-8. doi: 10.1021/jf402097y. Epub 2013 Aug 20.
Most protocols of sample preparation for isoflavone determination in soymilk and other liquid soybean products involves tedious freeze-drying and time-consuming extraction procedures. We report a facile and rapid magnetic solid-phase extraction (MSPE) of isoflavones from soymilk for subsequent high-performance liquid chromatography electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS) analysis. The extraction was based on the selective binding of isoflavones to baicalin-functionalized core-shell magnetic nanoparticles (BMNPs). The proposed MSPE-HPLC-MS/MS analytical method had a linear calibration curve in the concentration range from 0.3 to 80 mg/L isoflavones. With the use of calycosin, an isomer of one of the isoflavones targeted as an internal standard, interday (5 days) precisions of the slope and intercept of the calibration curves were found to be in the range between 2.5% and 3.6% (RSD, n = 5). Six isoflavones, that is, daidzein, glycitein, genistein, daidzin, glycitin, and genistin were detected in commercial soymilk samples and quantified by the proposed analytical method. The results indicated that the method was useful for fast determination of isoflavones in soymilk and other liquid soybean products.
大多数用于测定豆浆和其他液态豆制品中异黄酮的样品制备方案都涉及繁琐的冻干和耗时的提取程序。我们报告了一种从豆浆中快速简便地提取异黄酮的磁固相萃取（MSPE）方法，随后进行高效液相色谱-电喷雾串联质谱（HPLC-ESI-MS/MS）分析。该萃取方法基于异黄酮与黄芩苷功能化核壳型磁性纳米粒子（BMNPs）的选择性结合。所提出的 MSPE-HPLC-MS/MS 分析方法在异黄酮浓度为 0.3 至 80 mg/L 的范围内具有线性校准曲线。使用作为内标物的异黄酮之一的金雀异黄素的异构体，发现校准曲线斜率和截距的日内（5 天）精密度在 2.5%至 3.6%（RSD，n=5）之间。在商业豆浆样品中检测到六种异黄酮，即大豆苷、黄豆苷、染料木黄酮、大豆苷元、黄豆黄苷和染料木苷，并通过所提出的分析方法进行定量。结果表明，该方法可用于快速测定豆浆和其他液态豆制品中的异黄酮。
