提出了高效液相色谱法测定保健食品中α-硫辛酸含量的方法。样品用乙腈-水(4+6,预调至pH 3.5)混合液超声提取25 min,以C18色谱柱为分离柱,以上述乙腈-水混合液为流动相,在波长210 nm处进行测定。α-硫辛酸质量浓度在20.0~500 mg·L-1范围内与峰面积呈线性关系,方法检出限(3S/N)和测定下限(10S/N)分别为0.80 mg·L-1和2.7 mg·L-1。以空白样品为基体进行加标回收试验,所得回收率在91.5%~98.7%之间,相对标准偏差(n=5)小于5.0%。

A method of HPLC for determination of α-lipoic acid in health-care food was proposed. The sample was extracted ultrasonically with a mixture of acetonitrile and H2O (4+6, adjusted to pH 3.5) for 25 min. C18 chromatographic column was used as stationary phase, and the above mentioned mixture of acetonitrile and water was used as mobile phase. UV-detection at 210 nm was adopted in the determination. Linear relationship between values of peak area and mass concentration of α-lipoic acid was kept in the range of 20.0-500 mg·L-1, with detection limit (3S/N) and lower limit of determination (10S/N) of 0.86 mg·L-1 and 2.7 mg·L-1 respectively. On the base of a blank sample, test for recovery was made by standard addition method; values of recovery found were in the range of 91.5%-98.7% with RSD′s (n=5) less than 5.0%.