采用向量-子空间夹角判据测定酱油中的苯甲酸和山梨酸

Vector- subspace angle criterion in the determination of benzoic acid and sorbic acid in soy sauce

基于向量-子空间夹角判据结合紫外分光光度法,提出了一种新的方法同时测定酱油中的苯甲酸和山梨酸。通过构建不含被测组分苯甲酸和山梨酸的酱油本底紫外光谱库,苯甲酸和山梨酸标准品紫外光谱库,以及待测样品的紫外光谱数据,运用空间夹角判据计算市售酱油中的苯甲酸和山梨酸含量。根据苯甲酸和山梨酸易溶于有机溶剂,微溶于水的特性,首先对市售酱油进行酸化,使酱油中的苯甲酸钠和山梨酸钾转变为苯甲酸和山梨酸,然后再用乙醚为提取剂将苯甲酸和山梨酸从酱油中提取出来,最后采用水浴加热使乙醚挥发,冷却至室温再用甲醇定改为容,然后进行测定计算。实验结果表明:该方法计算结果与高效液相色谱法测定结果相对误差小于4.48%,苯甲酸和山梨酸的加标回收率为95.44%102.64%。

A new method was established based on vector-subspace angle criterion and UV spectrophotometer.In this study,three multi-wavelength of UV spectral libraries were constructed to compute the content of benzoic acid and sorbic acid in soy sauce by Vector-subspace angle criterion.The libraries include UV spectral libraries of soy sauce background,benzoic acid and sorbic acid standard compounds and samples.Benzoic acid and sorbic acid are freely soluble in organic solvent and slightly soluble in water,the sodium benzoate and potassium sorbate in soy sauce were turned into benzoic acid and sorbic acid in acidic conditions at first.Then the benzoic acid and sorbic acid were extracted from soy sauce with ethyl ether as extraction agent.And ethyl ether was evaporated by water heating,then the extraction solution adjusted volume with methanol in room temperature.At last,the content of benzoic acid and sorbic acid in soy sauce were determined and computerized.The results showed that：the relative error was less than 4.48％ when comparing the Vector-space angle criterion and high performance liquid chromatography.And the recoveries of benzoic acid and sorbic acid were 95.44％ ～ 102.64％.