超高效液相色谱-质谱联用法测定草莓中鞣花酸

Determination of Ellagic Acid in Strawberry by UPLC-MS/MS

建立了测定草莓中鞣花酸含量（包括游离鞣花酸和总鞣花酸）的超高效液相色谱-质谱联用（UPLCMS/MS）分析方法。草莓中游离鞣花酸在酸性条件下用甲醇提取,经C18分散固相萃取净化后可直接测定;总鞣花酸经酸性水解呈游离态再经分散固相萃取净化后进行测定。净化液经C18色谱柱分离,以甲醇和0.5%甲酸水为流动相进行梯度洗脱,电喷雾负离子（ESI-）模式电离,超高效液相色谱-质谱法（UPLC-MS/MS）测定,外标法定量。结果表明：在10-500 ng/m L浓度范围内鞣花酸的线性关系良好,相关系数为0.998 1,游离鞣花酸的定量下限为0.5 mg/kg,总鞣花酸的定量下限为5.0 mg/kg。在低、中、高3个加标浓度的回收实验中,游离鞣花酸的加标回收率为86.7%-113.6%,相对标准偏差均小于10%。该方法操作简单,灵敏度高,准确性好,适用于草莓中鞣花酸的测定。

Abs A method was developed for the determination of ellagic acid （ free ellagic acid and total el- lagic acid ） in strawberry by ultra performance liquid chromatography -tandem mass spectrometry （UPLC -MS/MS）. In this work, the free ellagic acid was extracted from strawberry with 0. 1% tri- floroacetric acid- methane, purified by C18 dispersive solid-phase extraction, and determined by UPLC- MS/MS. Total ellagic acid was hydrolyzed to free ellagic acid with 2 mol/L trifloroacetric acid aqueous, then purified with C18 dispersive solid-phase extraction column, and determined by UPLC -MS/MS. Sample solution was separated on a Cxa column by gradient elution using methanol - 0.5% formic acid aqueous as mobile phase. The linear range of 10 -500 ng/mL for ellagic acid was obtained, with correlation coefficient of 0. 998 1. The limit of quantitation was 0.5 mg/kg for free ellagic acid and 5.0 mg/kg for total ellagic acid. The recoveries at low, medium and high spiked lev- els ranged from 86.7% to 113.6% with relative standard deviations（RSD） not more than 10% . The results indicated that this approach was simple, sensitive and accurate, and was applicable for the determination of content of ellagic acid in strawberry.