The present research is focused on the setting up of an advanced analytical system for the detection of synthetic dyes. The system is based on the combination of an innovative thin layer chromatography (TLC) plate coupled with enhanced infrared (MU-ATR, metal underlayer attenuated total reflection) and Surface Enhanced Raman (SERS) spectroscopy. In particular, a TLC plate made of silver iodide (AgI) applied onto a gold coated glass slide (AgI@Au) is proposed as an efficient stationary phase for the separation of dyes mixtures. The separated dyes are then identified by means of both enhanced FTIR and SERS, performed directly on the same eluted spots. The use of a mid-IR transparent inorganic salt as stationary phase coupled with the underneath gold layer avoids spectral interferences, enhancing the signal obtained from ATR analyses. At the same time, SERS spectra can be recorded as the TLC plate may act as a SERS active substrate due to the photoreduction of AgI to metallic Ag caused by the exposure to the laser during the Raman analysis. Different mixtures of synthetic dyes of known composition, widely used in dyeing processes, have been tested and the method resulted to be effective in identifying trace amounts in the order of tens nanograms. Moreover, the method has been further evaluated on a real case study represented by dyes extracted from dyed wool.

中文翻译：

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一种新的集成 TLC/MU-ATR/SERS 高级方法，用于识别混合物中的痕量染料

目前的研究重点是建立先进的合成染料检测分析系统。该系统基于创新的薄层色谱 (TLC) 板与增强红外 (MU-ATR，金属底层衰减全反射) 和表面增强拉曼 (SERS) 光谱的组合。特别是，将碘化银 (AgI) 制成的 TLC 板涂在镀金载玻片 (AgI@Au) 上，被提议作为分离染料混合物的有效固定相。然后通过增强型 FTIR 和 SERS 识别分离的染料，直接在相同的洗脱点上进行。使用中红外透明无机盐作为固定相与下面的金层相结合，避免了光谱干扰，增强了从 ATR 分析中获得的信号。同时，由于在拉曼分析过程中暴露于激光导致 AgI 光还原为金属 Ag，TLC 板可以作为 SERS 活性基板，因此可以记录 SERS 光谱。已经测试了广泛用于染色过程的已知成分的合成染料的不同混合物，结果该方法可有效识别数十纳克数量级的痕量染料。此外，该方法已在以从染色羊毛中提取的染料为代表的真实案例研究中得到进一步评估。经测试，该方法可有效识别数十纳克量级的痕量。此外，该方法已在以从染色羊毛中提取的染料为代表的真实案例研究中得到进一步评估。经测试，该方法可有效识别数十纳克量级的痕量。此外，该方法已在以从染色羊毛中提取的染料为代表的真实案例研究中得到进一步评估。