Raman Spectroscopy Group, University Analytical Centre, Division of Chemical and Forensic Sciences, University of Bradford, West Yorkshire BD7 1DP, UK.
Spectrochim Acta A Mol Biomol Spectrosc. 2010 May;75(5):1403-10. doi: 10.1016/j.saa.2010.01.008. Epub 2010 Feb 4.
Molecular speciation of organic compounds in solution is essential for the understanding of ionic complexation. The Raman technique was chosen because it allows the identification of compounds in different states, and it can give information about the molecular geometry from the analysis of the vibrational spectra. The effect of pH on organic compounds can give information about the ionisation of molecule species. In this study the ionisation steps of salicylic acid and paracetamol have been studied by means of potentiometry coupled with Raman spectroscopy at 30.0 degrees C in a solution of ionic strength 0.96moldm(-3) (KNO(3)) and 0.04moldm(-3) (HNO(3)). The protonation and deprotonation behaviour of the molecules were studied in different pH regions. The abundance of the three different species in the Raman spectra of aqueous salicylic acid have been identified satisfactorily, characterised, and determined by numeric treatment of the data using a multiwavelength curve-fitting program and confirmed with the observed spectral information.
溶液中有机化合物的分子形态对于理解离子络合至关重要。选择拉曼技术是因为它可以识别不同状态的化合物，并且可以通过分析振动光谱来提供分子几何形状的信息。pH 值对有机化合物的影响可以提供有关分子物种电离的信息。在这项研究中，通过电位滴定法与拉曼光谱相结合，在离子强度为 0.96moldm(-3)（KNO(3)）和 0.04moldm(-3)（HNO(3)）的溶液中，于 30.0°C 下研究了水杨酸和扑热息痛的电离步骤。在不同的 pH 区域研究了分子的质子化和去质子化行为。通过使用多波长曲线拟合程序对数据进行数值处理，以及通过观察到的光谱信息进行确认，已经满意地识别、表征和确定了水相中水杨酸的三种不同物种在拉曼光谱中的丰度。
