A multi-component optimisation of experimental parameters for maximising SERS enhancements

We present a multi-component optimisation strategy for a range of commonly used Ag colloids as surface-enhanced Raman scattering (SERS) spectroscopy substrates. The concentration-dependent interactions of a wide range of parameters, including colloid and aggregating agent species, were considered in order to achieve optimal SERS enhancements. Few papers in the literature discuss the optimisation of these parameters, never mind multi-component optimisation, and suboptimal responses result in SERS not being utilised to its true capabilities. Significant differences in enhancement factor were observed as a consequence of colloid-aggregating agent interactions and these are shown to be analyte specific. Both the cation and anion of the aggregating agent were found to play an important role in the optimisation process. We show that through the optimisation of experimental conditions, the reliability and applicability of SERS can be significantly improved.