FLUORESCENCE LINE-NARROWING SPECTROSCOPY AS AN OFF-LINE IDENTIFICATION METHOD FOR NARROW-BORE COLUMN LIQUID-CHROMATOGRAPHY

Storage of the effluent from a column liquid chromatograph (LC) on a t hin-layer chromatography (TLC) plate was utilized to identify analytes with fluorimetric techniques in the absence of time constraints. As a n example, the deposited LC trace of an impure 1-chloropyrene sample w as studied in situ by conventional excitation/emission spectroscopy an d by fluorescence line-narrowing (FLN) spectroscopy, a high-resolution laser-induced fluorescence technique requiring cryogenic conditions. Pyrene and several mono-, di-, and trichlorinated pyrenes, present in the 1-chloropyrene sample, were identified with the use of the fingerp rint structure of the vibrationally resolved FLN spectra. Quantitation on the basis of the FLN signals was achieved by standard addition; co mpounds could be detected down to the low picogram level. Various TLC materials were used to study the influence of the matrix on the FLN sp ectra; although peak intensities and hole burning effects are matrix-d ependent, the line positions are not influenced.