Critical evaluation of experimental conditions influencing the surface-enhanced Raman spectroscopic (SERS) detection of substances separated by layer liquid chromatographic techniques

Abstract

SummarySurface-enhanced Raman spectra (SERS) of p-dimethylaminobenzylidenerhodanine have been recorded on silica gel 60 F254 and Si60 F254 Raman TLC plates. Spectra were enhanced by use of a silver sol prepared according to the modified Lee-Meisel procedure. The standard deviations of the intensities and the band ratios for the seven most intense peaks were calculated for 30 parallel measurements. Although the Raman plate gives more reproducible results, several experimental difficulties are encountered in the development of chromatograms. SERS detection ofascorbigen and 1 '-methylascorbigen was performed after chromatography on silica gel 60 F254 TLC and HPTLC plates and on Si60 F254 Raman TLC plates. Traditional development was used for the silica gel 60 F254 TLC plates and Si60 F254 Raman plates, and the personal OPLC technique for the silica gel 60 F254 HPTLC plates. It was found that the SERS spectrum gave information about the indole ring only. Because bonding of the analyte to the stationary phase results in a change in molecular conformation-in contrast with the behaviour of rhodanine-the type of the plate used and the development procedure employed can significantly influence the quality of the SERS spectrum.

At-line coupling of capillary electrophoresis and surface-enhanced resonance Raman spectroscopy

“…The first experiments indicate that analyte confirmation can be achieved down to a few pmoles deposited on the TLC plate. This is of marked interest, since TLC -SER(R)S has received much attention in the literature (see e. g. [17]). Generally speaking, the robustness of the set-up was found to be satisfactory throughout the 5-month duration of the study.…”

SERS and Separation Science

“…Using citrate-reduced silver colloids, which had been pre-aggregated through the addition of sodium perchlorate, the authors were able to record clear micro-FT SERS spectra of the carotenoid, crocetin, at 10 −5 M concentration and calculated that this corresponded to an analysed mass of 0.02 fg [27]. Other experimental factors, including the choice of metal used for the SERS surface, development method and laser excitation wavelength, that affect the success of TLC-SERS measurements have been discussed in more detail by Kocsis et al [28] and Horvarth et al [29].…”

Basic TLC Techniques, Materials, and Apparatus

“…Methods for silica gel layer preactivation include dipping the plate into a solution of silver oxalate and subsequently pyrolyzing it to form silver particles on the layer (210), vacuum evaporation (211), and citrate reduction (212). It was found that the type of plate and the development procedure (traditional vs. OPLC) influenced significantly the quality of SERS spectra obtained (213). NIR-SERS was shown to be useful for both qualitative and quantitative analysis in a single step (214).…”