Inherent Complexities of Trace Detection by Surface‐Enhanced Raman Scattering

Abstract

Surface-enhanced Raman scattering (SERS) and surface-enhanced resonance Raman scattering (SERRS) are powerful optical scattering techniques used in such frontier areas of research as ultrasensitive chemical analysis, the characterization of nanostructures, and the detection of single molecules. However, measuring and, most importantly, interpreting SERS/SERRS spectra can be incredibly challenging. This is the result of modifications to the measured spectra that are due to of a variety of instabilities and contributions. These interferences and modifications arise from the nature of the enhancement itself, as well as the conditions used to attain SERS spectra. The present report is an attempt to collect in one place the analytical interferences that are most commonly found during the collection of SERS/SERRS spectra.

Surface-Enhanced Raman Spectroscopy

“…For example, a thin layer of gold or silver, typically between 5 and 10 nm, was vapor deposited onto a slide, resulting in a collection of thin island films capable of supporting surface plasmons. Although a small amount of tunability is possible through the modification of film Nanosphere lithography (NSL): deposition mask formed by self-assembly of hexagonally close-packed nanospheres thickness and solvent annealing, variations and a lack of information regarding the SERS active sites prevented a quantitative application of SERS (56,57). The past decade has seen significant advances in both the understanding and applications of SERS.…”

Surface-enhanced Raman spectroscopy studies of organophosphorous model molecules and pesticides

“…14 Under such conditions there is a variation in the spectral pattern, since the observed signal is not an average result. 15 Above a certain limit of the adsorbate concentration on the surface, where an average SERS spectrum can be obtained, the use of a regular and ordered metallic substrate allows us to quantify the mother-solution concentration, making possible the analytical use of such a technique and the detection of species in trace levels. As a consequence, the use of the SERS technique has been gaining increasing importance to analytical applications in areas such as environmental, 16 biological 17 and forensic chemistry.…”

Light at work: The use of optical forces for particle manipulation, sorting, and analysis

“…Comparison of normal Raman and SERS spectra reveals not only an enhancement of the normal Raman spectral features but also the appearance of spectral features absent in the normal Raman spectrum and shifts of the spectral peaks caused by various effects (chemisorption or chemical bonding, polarizability variations, change in the transition selection rules due to the molecule-substrate coupling, etc.) [439]. …”