连续波长紫外分光光度法对合成食用色素混合体系的同时定量测定

提出一种用连续波长的紫外光谱吸光度数据对多组分合成食用色素的定量分析方法。该方法利用连续波长信息把吸光系数和待测浓度同时作为自变量,建立非线性优化模型,对于组分浓度差较小的混合物体系经一次优化分析可得待测浓度。混合物中浓度差较大的体系经四次左右优化迭代,逐步降低误差得分析结果。利用本法对四组分混合色素体系分析结果表明,该法稳定、准确、简便快速、实用灵活,可对色素混合物体系进行定量测定。

The simultaneous multi -component quantitative determination of mixed edible pigments was proposed using continuous wavelength ultraviolet spectrophotometry without any chemical separation procedure, The method treats the absorbance coefficient and component concentration of solutions as independent variables at the same time and sets up a constrained optimization model to solve it by generalized reduced gradient. The concentration awaiting test can be obtained after one optimization calculation to the mixed solution in which the concentration of every component is close to each other.But to some solutions in which component concentration is not close to each other, repeated optimization is necessary. The final results obtained are satisfatory with a good accuracy and precision only after about 4 times of repeated optimization. So this method can be used to determine mixed edible pigments quantitatively.