导数同步荧光光谱法同时测定食品中的合成色素

建立了测定食品中胭脂红和日落黄的一阶导数同步荧光光谱法。研究了胭脂红和日落黄在不同pH值溶液中的同步荧光光谱特征，确定了同步荧光光谱的最佳波长差。当Δλ=130 nm时，胭脂红和日落黄导数同步荧光光谱的零交点位于313.6和302.8 nm，可分别测定日落黄和胭脂红的含量。胭脂红在0.1~4.0 mg·L-1、日落黄在0.1~2.0 mg·L-1范围内浓度与导数同步荧光值呈线性，相关系数(R2)为0.999 2和0.996 6;检出限为0.041和0.019 mg·L-1;相对标准偏差(RSD)为4.8%和4.6%。 回收率在91.0%~110%之间。 测定结果与导数-分光光度法的结果相一致，具有简便、 快捷等特点，能够同时测定食品中胭脂红和日落黄的含量。

Derivative Synchronous Fluorimetry for Determination of Synthetic Food Dyes in Food

The first order derivative synchronous fluoremetry was proposed for simultaneous determination of sunset yellow and ponceau 4R. The effect of different experimental conditions, such as different pH for character of fluorescence spectra and the choosing of the optimal wavelength difference were studied. It was showed that the zero-crossing points were at 313.6 nm for ponceau 4R and at 302.8 nm for sunset yellow in first order derivative synchronous fluorescence spectra. Therefore, 313.6 and 302.8 nm were selected for the determination of sunset yellow and ponceau 4R when Δλ=130 nm. This method could minimize interference without preseparation. The linear ranges of sunset yellow and ponceau 4R were from 0.1 to 2.0 mg·L-1 and from 0.1 to 4.0 mg·L-1 with correlation coefficient 0.996 6 and 0.999 2, the detection limits were 0.041 and 0.019 mg·L-1, RSDs were 4.6% and 4.8% (n=6), respectively. The recoveries varied from 91.0% to 110%. The proposed method was successfully applied in simultaneous determination of sunset yellow and Ponceau 4R in food.