The Combination of High-Resolution Molecular Fluorescence Spectroscopy with Liquid Chromatography and Thin-Layer Chromatography

Abstract

Under certain conditions, highly specific fluorescence spectra, showing molecular vibrations as in infrared spectroscopy, can be obtained for the analysis of compounds separated in TLC and microbore LC. Two techniques, both employing low-temperature solid samples, are available: Shpol'skii spectroscopy and Fluorescence Line-Narrowing (FLN) spectroscopy. The former utilizes n-alkane solvents, which form regular, crystalline solids; the latter is based on selective laser excitation. Both techniques can be applied for detection in TLC. FLN is more feasible, since the Shpol'skii method requires spraying of the TLC plate, which leads to significant spreading of the spots. FLN can also be used for offline detection in micro-LC after immobilization of the column effluent on a TLC plate. In addition, some exploratory experiments on the applicability of FLN for on-column detection in LC are presented.