SURFACE-ENHANCED RESONANCE RAMAN-SPECTROSCOPY OF LIQUID-CHROMATOGRAPHIC ANALYTES ON THIN-LAYER CHROMATOGRAPHIC PLATES

Surface-enhanced resonance Raman spectroscopy (SERRS) was incorporated as a detector for a liquid chromatography (LC)-coupled thin-layer chromatography (TLC) system. In this SERRS/LC/TLC system, effluent from the LC system was deposited onto the surface of a solid supporting matrix (TLC plate) with a modified XY plotter under computer control. An activated Ag sol was added to the plate (enhancing substrate) and then interrogated with a remote-sensing Raman spectrometer. Optical fibers carried the excitation light to the TLC plate and the scattered Raman radiation to the spectrometer for analysis. The dye, pararosaniline acetate, was found to give a linear SERRS signal over the concentration of 1 X 10–5 to 1 X 10-7 M range. The limit of detection was 750 fmol. The advantages of the LC/TLC system with SERRS detection, In comparison to conventional solution phase SERRS, is that the solid matrix prevents the continued aggregation of the Ag/dye complex, thereby giving stable signals for extended periods of time. With the proper choice of matrix for the adsorption process, enhanced SERRS intensities are observed. The analytes are stored, decoupling the analysis from the LC flow. Acquisition of the SERRS spectrum can therefore be taken at whatever convenient time and long Integration times can be used to improve the signal-to-noise ratio. © 1990, American Chemical Society. All rights reserved.