Surface-enhanced resonance Raman scattering fluorescence

Surface enhanced resonance Raman scattering (SERRS) is an analytical technique with several advantages over competitive techniques in terms of improved sensitivity and selectivity. We have made great progress in the development of SERRS as a quantitative analytical method, in particular for the detection of DNA. However, one of the main advantages over fluorescence and other optical detection techniques is the ability to multiplex. 

Sabatte, G., Keir, R., Lawlor, M., Black, M., Graham, D., and Smith, W.E. (2008) Comparison of surface-enhanced resonance Raman scattering and fluorescence for detection of a labeled antibody. Analytical Chemistry, 80, 2351-2355. 

Raman spectroscopy Raman and resonance Raman spectroscopy have also been applied to the analysis of inks on paper. These techniques allow the chemical characterization of the ink but were reported to be lacking in sensitivity and to be highly influenced by fluorescence effects caused by papers. Surface enhanced resonance Raman scattering spectroscopy... 

Surface-enhanced resonance Raman scattering was originally reported by Stacy and Van Duyne in 1983 [2], The advantages of SERRS, namely a significant increase in the Raman signal observed by up to a factor of 10 and the quenching of fluorescence, have been well documented in the literature [3-8]. A book detailing the key papers in the early development of the technique was written by Kerker [9]. 

Surface-enhanced resonance Raman scattering causes fluorescence quenching. It is very often possible to identify SERRS spectrum from a dye in a matrix where resonance Raman scattering is completely obscured by the fluorescence. 

SERS offers considerable promise for the study of polymers for several reasons. The enhancement effect can increase Raman scattering by a factor of 10 -10 . Adsorption of molecules on the SERS-active metal surface causes fluorescence quenching in highly fluorescent compounds. In addition, surface-enhanced resonance Raman scattering can further enhance the Raman scattering efficiency by a factor of 10 -10 above that observed under resonance or surface-enhanced conditions alone. 

Weitz D. A., Garo S., Gersten J. L, and Nitzan A. (1983). The enhancement of Raman scattering, resonance Raman scattering and fluorescence fi-om molecules adsorbed on a rough silver surface. J. Chem. Pl. 78 5324-5338. 

The quantum yield of the classical (or so-called linear) Raman effect is rather poor. Only a fraction of to 10 of the exciting photons are converted into Raman photons. This excludes the detection of low concentration analytes. Moreover, due to the quantum yield of fluorescence, even traces of fluorescent impurities may mask the Raman signal by their fluorescence. Therefore, there has been much scientific effort towards the development of Raman based methods which allow one to overcome this problem. Methods to overcome these problems are Resonance Raman Scattering and Surface Enhanced Raman Scattering. 

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