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建立了甲基紫共振光散射光谱法测定饮料中日落黄的方法。在pH 3的B-R缓冲溶液中,日落黄与甲基紫之间相互作用形成离子缔合物,引起共振光散射强度的显著增加。共振光散射峰分别位于339 nm和650 nm处,在650 nm处,共振光散射强度与日落黄质量浓度在0.02～0.2 mg/L范围内呈现良好的线性关系(r2=0.9981)。考察了酸度、甲基紫用量、离子强度、温度等对体系光散射强度的影响,测定了缔合物的组成比。方法的检出限为7.5μg/L,相对标准偏差(RSD)为2.1%。方法用于饮料样品中日落黄的测定,结果与紫外分光光度法一致。
A method was developed for the determination of sunset yellow in beverage by methyl violet resonance light scattering spectrometry. In the pH 3 B-R buffer solution, the interaction between sunset yellow and methyl violet forms an ion association that causes a significant increase in the intensity of resonant light scattering. Resonance light scattering peaks were at 339 nm and 650 nm, respectively. At 650 nm, there was a good linear relationship (r2 = 0.9981) between the intensity of the scattered light and the concentration of sunset yellow in the range of 0.02-0.2 mg / L. The effects of acidity, methyl violet content, ionic strength and temperature on the light scattering intensity of the system were investigated. The composition ratio of the complexes was determined. The detection limit of the method was 7.5 μg / L, with a relative standard deviation (RSD) of 2.1%. The method was applied to the determination of sunset yellow in beverage samples. The result was consistent with the UV spectrophotometry.