在分析复杂混合物方面原位薄层色谱-红外光谱联用有巨大潜力, 二者联用能够相互取长补短, 极大地提高对复杂混合物的解析能力。 但因固定相自身的红外吸收能够对样品的检测造成干扰, 使该方法进展缓慢。 实验应用对中红外光透明的碘化银纳米微粒作为固定相制备薄层层析板, 并对碘化银薄层板的层析效果及原位红外光谱检测的可行性进行了初步的研究。 通过正交设计实验法优化反应条件, 制备出粒径为100 nm左右的碘化银颗粒; 应用沉降-挥发法制备薄层层析板, 实验表明该薄层板具备分离混合物的能力, 且原位红外光谱检测结果表明碘化银作为固定相不干扰样品检测。

In situ TLC/FTIR technique has tremendous potential in the analysis of complex mixtures. However, the progress in this technique was quite slow. The reason is that conventional stationary phase has strong absorption in FTIR spectrum and thus brings about severe interference in the detection of samples. To solve the problem, the authors propose to use AgI fine particles as stationary phase of TLC plate. The reasons are as follows: Silver iodide fine particles have no absorbance in an IR region between 4 000 and 800 cm-1, therefore, the interference caused by IR absorption of stationary phase can be removed. Moreover, silver iodide is stable and insolvable in water and organic solvents and thus it will not be destroyed by mobile phase or react with samples during the TLC separation. To improve TLC separation efficiency and quality of FTIR spectra during the TLC/FTIR analysis, the size of AgI particles should be below 500 nm. We used orthogonal design approach to optimize the experimental condition to AgI particles so that the average size of AgI particles is around 100 nm. No absorption of impurity or adsorbed water were observed in FTIR spectrum of the AgI particles the authors used “settlement volatilization method” to prepare TLC plate without using polymeric adhesive that may bring about significant interference in FTIR analysis. Preliminary TLC experiments proved that the TLC plate using AgI fine particles as stationary phase can separate mixtures of rhodamine B and bromophenol blue successfully. Applications of silver iodide fine particles as stationary phase have bright perspective in the development of in-situ TLC/FTIR analysis techniques.