Thermo-Optical Spectroscopy: New and Sensitive Schemes for Detection in Capillary Separation Techniques

Abstract

Detection is a major problem in the application of Open-Tubular Capillary Liquid Chromatography (OTCLC) and Capillary Electrophoresis (CE) for analyzing very dilute samples, for instance in trace analysis. Thermo-optical Spectroscopy is a new branch of Spectroscopy which allows the detection of samples with low light absorbances (10⁻⁸ −10⁻⁹ AU) using a few picoliters sample cell. A few attomoles of analyte can be detected in OTCLC or in CE with these techniques. These results are similar to those achieved by Laser-Induced Fluorescence detection in open-tubular capillary tubings. However, many organic substances present a high absorption coefficient and only a few of them provide good quantum yields. The principles of Thermo-optical Spectroscopy are presented in this work. The main thermo-optical methods and their application in OTCLC and CE are also reviewed