Practical Aspects of SERS

In the case of successful SERS measurement, some differences between SERS and NRS spectrum of analyte should be taken into account  

SERS spectrum is affected by the LSPR of metallic substrates which is wavelength dependent. Thus, the peaks in the SERS spectrum can be enhanced by a different factor depending on LSPR of metallic substrate and a particular vibration frequency. 

Surface selection rules for SERS are generally different from that for NRS, as the symmetry of the molecular nuclear and/or electron arrangement may be disturbed or even broken at the surface. Thus, the orientation of the molecule relative to the surface normal is important and can be detected flat versus tilted versus perpendicular orientations give rise to distinct SERS signatures since the various vibrational bands of the adsorbed molecule, e.g., bands due to in plane and out of plane modes of an aromatic compound are differently enhanced according to the corresponding components of the tensor ttmoiecuie- 

Some analytes can strongly interact with a metal surface, even forming a surface complex in some cases. Therefore, SERS spectrum can differ from that of NRS in the absence of metal. The interaction of some biomolecules, such as proteins. 

3 Basics of Surface-Enhanced Raman Scattering (SERS) 

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