在pH 4.2的乙酸-乙酸钠缓冲溶液中,甲基紫与阿魏酸反应生成具有负吸收峰的紫色络合物。其最大负吸收波长位于565 nm,阿魏酸的质量浓度在0.1~3.9 mg·L-1范围内与吸光度呈线性关系,服从比耳定律,表观摩尔吸光率(ε)为4.36×104L·mol-1·cm-1。方法用于市售药物中阿魏酸钠含量的测定,回收率在99.5%~103%之间,测定值的相对标准偏差(n=6)在1.3%~1.5%之间。

In HOAc-NaOAc buffer solution at pH 4.2, methyl violet could react with ferulic acid to form purple complexes with an obvious negative absorption peak. The maximum negative absorption wavelength was at 565 nm. Linear relationship between values of absorbance and mass concentration of ferulic acid was obtained in the range of 0.1-3.9 mg·L-1 , consistent with Beer′s law. The apparent molar absorptivity (ε) was 4.36×104L·mol-1·cm-1. The method was applied to the determination of sodium ferulic acid in commercially available sodium ferulic acid, giving values of recovery and RSD in the ranges of 99.5%-103% and 1.3%-1.5% respectively.