三波长-光谱法测定沙棘果汁中黄酮的含量

以沙棘果汁为对象，对其主要有效化学成分黄酮类化合物总含量进行了测定分析。一般常用的分光光度法存在一定的缺陷，加入铝盐使黄酮类化合物与铝离子形成稳定的配合物，则吸收带Ⅰ会明显产生红移，同时吸光度也大大增加，但由于干扰成分使吸收峰不对称给定量分析造成一定的影响。文章采用三波长-光谱法测定沙棘果汁中黄酮的含量，有效地消除了随浓度不同产生的本底漂移及吸收峰不对称给定量分析造成的影响，并校正了基于干扰组分的吸收光谱具有线性吸收产生的基线倾斜，实验结果，回归方程为: ΔA=-0.007 03＋0.000 48ｃ，相关系数r=0.999 1，黄酮的浓度在0～800 (μg·mL-1)范围内，分别在波长为λ₁=495 nm, λ₂=415 nm, λ₃=368 nm处测吸光度时，则ΔA与浓度ｃ之间呈良好的线性关系，可按标准曲线法进行定量分析。本法的回收率为97.0%～101.0%, 变异系数小于0.058%(n=9)。方法的准确度与精密度均令人满意，而且操作简便易行。

Quantitative Determination of Total Flavonoids in Sea-Buckthorn Fruit Juice by Three Wavelength Spectrophotometry

Numerous studies dealing with the quantitative determination of total flavonoids in sea-buckthorn fruit juice by spectrophotometry are presented. The flavonoids in sea-buckthorn fruit juice and aluminate produce stable complex whose absorption occurred at longer wavelength. To determine the total flavonoids in sea-buckthorn fruit juice by traditional spectrophotometry method, baseline shift and asymmetric absorption peak occurred on the absorption curve. Quantitative determination of flavonoids in sea-buckthorn fruit juice by three wavelength spectrophotometry method can eliminate the absorbance error caused interfering components in turbid solution and the scattering effect. Background changing with the concentration change and asymmetric absorption peak problems can also be solved. The regression equation of concentration vs deltaA was obtained: deltaA = - 0.00703 + 0.00048c with a relation coefficient gamma = 0.9991. The experimental results demostrate the total flavonoids concentrations in 0-800 microg x mL(-1) with deltaA obeying linear relation when the absorbance was measured at wavelength lambda1 = 495 nm, lambda2 = 415 nm and lambda3 = 368 nm. The recovery is 97.0%-101.0% and the coefficient of variation is 0.058% (n = 9). The method is more advantageous than tranditional spectrophotometry method.