简便吸收光谱法测定饮料中共存色素诱惑红和柠檬黄

Determination of coexisting pigments allure red and tartrazine in beverages by simple absorption spectrometry

建立了同时测定饮料中共存色素诱惑红和柠檬黄的简便吸收光谱法。在pH 7.2~8.7 Tris-HCl介质中,诱惑红和柠檬黄与双绿SF反应生成离子缔合物。诱惑红-双绿SF在可见光区有正吸收峰(496 nm)和负吸收峰(570 nm),诱惑红的质量浓度在0.03~12.4 mg/L范围内服从朗伯-比尔定律,表观摩尔吸光系数为1.79×10^(4)L/(mol·cm)(496 nm)和2.43×10^(4)L/(mol·cm)(570 nm),检出限为29μg/L(496 nm)和27μg/L(570 nm),定量限分别为0.78 mg/kg和0.73 mg/kg。柠檬黄-双绿SF在422 nm和660 nm处分别产生1个较强的正吸收峰,柠檬黄的质量浓度在0.04~13.4 mg/L范围内服从朗伯-比尔定律,表观摩尔吸光系数为2.13×10^(4)L/(mol·cm)(422 nm)和1.59×10^(4)L/(mol·cm)(660 nm),检出限为32μg/L(422 nm)和35μg/L(660 nm),定量限分别为0.87 mg/kg和0.95 mg/kg。当用双波长法测定时,表观摩尔吸光系(κ)为4.22×10^(4)L/(mol·cm)(诱惑红体系)和3.72×10^(4)L/(mol·cm)(柠檬黄体系),诱惑红体系的检出限和定量限分别为0.014 mg/L和0.38 mg/kg,加标回收率和相对标准偏差分别为98.0%~102%和2.3%~2.8%;柠檬黄体系的检出限和定量限分别为0.017 mg/L和0.46 mg/kg,加标回收率和相对标准偏差分别为97.5%~103%和1.1%~2.2%。该法适于饮料中诱惑红和柠檬黄的测定。

A simple absorption spectroscopy method was established for the simultaneous determination of coexisting pigments allura red and tartrazine in beverages.In the Tris-HCl(p H 7.2-8.7)medium,allure red and tartrazine reacted with double green SF to form ionic association complex.Allurared-double green SF produced a positive absorption peak(496 nm)and a negative absorption peak(570 nm)in the visible light region.The Lambert-Beer’s law was obeyed for allurared in the concentration from 0.03 to 12.4 mg/L,showing that the apparent molar absorption coefficients(κ)were 1.79×10^(4) L/(mol·cm)(496 nm)and 2.43×10^(4) L/(mol·cm)(570 nm),the detection limits were 29μg/L(496 nm)and 27μg/L(570 nm),and the quantitative limits were 0.78 mg/kg and 0.73 mg/kg,respectively.Tartrazine-double green SF produced a strong positive absorption peak at 422 nm and 660 nm,respectively.The Lambert-Beer’s law was also obeyed for tartrazine in the concentration from 0.04 to 13.4 mg/L,showing that the apparent molar absorption coefficients(κ)were 2.13×10^(4) L/(mol·cm)(422 nm)and 1.59×10^(4) L/(mol·cm)(660 nm),the detection limits were 32μg/L(422 nm)and 35μg/L(660 nm),the quantitative limits were 0.87 mg/kg and 0.95 mg/kg,respectively.When measured by the dual-wavelength method,the apparent molar absorption coefficients(κ)were 4.22×10^(4) L/(mol·cm)(allurared system)and 3.72×10^(4) L/(mol·cm)(tartrazine system),the detection limit and quantification limit of allurared system were 14μg/L and 0.38 mg/kg,respectively,and the spiked recoveries and relative standard deviations were 98.0%-102%and 2.3%-2.8%,respectively;while the detection limit and quantification limit of tartrazine system were 17μg/L and 0.46 mg/kg,respectively,and the spiked recoveries and relative standard deviations were 97.5%-103%and 1.1%-2.2%,respectively.This method was suitable for the determination of coexisting pigments allura red and tartrazine in beverages.