Validation of Plate-type Cell for Micro-Raman Analysis of Liquid Sample

Abstract

Recently, the use of the Micro-Raman spectrometer for the analysis of chemical materials is attracting attention in applied chemistry and advanced technologies due to the easiness of measurement. However, in the case of a liquid sample, there is some difficulty to analyze it, especially in focusing the laser beam on a transparent liquid sample accurately by using conventional vessels, such as the NMR tube and capillaries. We report here on the validation of a newly-designed cell for Micro-Raman spectroscopy that could more easily analyze a liquid sample than using conventional vessels. This cell is a small rectangular block (30×30×15 mm) made of aluminum alloy having a cylindrical hole (Φ10×5 mm) at center of the surface. First, the hole is filled with an aqueous solution or organic solvent, and then covered with a thin glass plate. By focusing the laser beam anywhere on the bottom surface of the hole, a high signal with sufficient intensity is easily detected. Similarly, a measurement using a cell made of another material, such as stainless steel, glass or polypropylene (PP) is tested. Finally, we conclude that aluminum alloy is the most suitable to be used for the cell material, due to its overall signal intensity, workability of material, low cost, resistance to chemicals and no interference to the Raman signal.