Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, PR China.
State Key Laboratory of Nuclear Physics and Technology, Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing 100871, PR China.
Spectrochim Acta A Mol Biomol Spectrosc. 2023 Aug 5;296:122598. doi: 10.1016/j.saa.2023.122598. Epub 2023 Mar 24.
An apparatus and relevant approach to obtaining IR spectra of solutes from the corresponding aqueous solution were developed. In the experiment, aqueous solutions were converted into aerosols using an ultrasonic or a pneumatic device. Subsequently, water in the nebulized solution is completely gasified under a high-speed flow and low vacuum environment. Via this process, the aqueous solution changes into a mixture of a solute or solutes and gaseous water, whose single-beam IR spectra are collected. Then, the newly developed RMF (retrieving moisture-free IR spectrum) method and the relevant approach described in our recent papers have been adopted to treat the resultant single-beam sample spectrum. As a result, the spectral contribution of the vibrational-rotational peaks of gaseous water can be removed or significantly attenuated, and IR spectra of solutes can be obtained. The approach shows an obvious advantage in retrieving the IR spectrum of volatile solutes from its aqueous solution. This capability is showcased by obtaining IR spectra of isopropanol and ethyl acetate successfully. IR spectra of these compounds can be retrieved even if the concentration of the solute is below 10 wt%. Moreover, atomization via ultrasonic/pneumatic methods offers a mild way to gasify solutes whose boiling points are remarkably higher than that of water. This advantage is manifested by acquiring IR spectra of 1-butanol and 1,2-propanediol in the gaseous phase under ambient conditions.
开发了一种从相应水溶液中获取溶质红外光谱的仪器和相关方法。在实验中，使用超声或气动装置将水溶液转化为气溶胶。随后，在高速气流和低真空环境下，雾化溶液中的水完全气化。通过这个过程，水溶液变成了溶质或溶质和水蒸气的混合物，其单光束红外光谱被收集。然后，采用新开发的 RMF（检索无湿红外光谱）方法和我们最近的论文中描述的相关方法来处理所得的单光束样品光谱。结果，水蒸气的振动-旋转峰的光谱贡献可以被去除或显著衰减，从而得到溶质的红外光谱。该方法在从水溶液中检索挥发性溶质的红外光谱方面具有明显的优势。通过成功获得异丙醇和乙酸乙酯的红外光谱证明了这一能力。即使溶质的浓度低于 10wt%，也可以检索到这些化合物的红外光谱。此外，通过超声/气动方法雾化提供了一种温和的方式来气化沸点明显高于水的溶质。这一优势体现在通过在环境条件下在气相中获得 1-丁醇和 1,2-丙二醇的红外光谱上。
