化学
银纳米粒子
表面等离子共振
光散射
荧光
分析化学(期刊)
纳米颗粒
检出限
散射
氧化还原
激光指示器
光化学
共振(粒子物理)
激光器
色谱法
纳米技术
光学
无机化学
原子物理学
材料科学
物理
作者
Li Wu,Yuan Li,Cheng Zhi Huang,Qin Zhang
摘要
A visual light scattering detection method of Sudan dyes is reported in food products based on the formation of silver nanoparticles (NPs) . Sudan dyes including I, II, III and IV have reducibility due to the nitrogen-nitrogen double bond and phenol group in their molecular structure, and a redox reaction could occur with AgNO3. Owing to the formation of silver NPs as a result of the redox reaction, color changes could be observed by eye from the red of Sudan to the brown of silver NPs, resulting in strong plasmon resonance light scattering (PRLS) signals characterized at 452 nm, which could be measured using a common spectrofluorometer. It was found that the PRLS intensities were proportional to the dye concentrations over the range of 0.2-2.4 microM Sudan I, 0.1-2.4 microM Sudan II, 0.1-2.4 microM Sudan III, and 0.2-3.0 microM Sudan IV, with the corresponding limits of determination (3 sigma) of 3.2, 3.0, 3.2, and 2.9 nM, respectively. Using hot chili as a model sample, detection could be made with the recovery of 90.8-103.3% and RSD of 4.0-4.9%, and the results are identical with that of a liquid chromatographic method approved by the European Commission. To make the PRLS method much more practical, we could visually detect the quantity of Sudan dyes based on the PRLS signals using simple devices such as a portable laser pointer (653 nm) and a light emitting diode (458 nm). Mechanism investigations show that the functional group of Sudan oxidized by AgNO3 is the phenol group, not the nitrogen-nitrogen double bond.
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