Reliable Methodology for Measuring SERS Enhancement Factor on Colloidal and Solid Substrates: A Practical Guide

ABSTRACT This study presents a robust and practical methodology for quantifying the Surface‐Enhanced Raman Spectroscopy (SERS) Enhancement Factor (EF) on both colloidal and solid substrates. SERS, a powerful technique for enhancing the Raman signals of analytes near plasmonic surfaces, has found extensive applications in fields such as biomedicine and materials science. However, inconsistencies in EF measurement methods have hindered cross‐comparisons between different SERS substrates. This work addresses these challenges by providing a standardized protocol for EF determination for a wide variety of substrates composed of gold and silver nanoparticles, as well as nanostructured surfaces. Using p‐mercaptobenzoic acid (p‐MBA) as a model non‐resonant probe, the approach accounts for key variables including substrate geometry, sampling volume, and substrate inhomogeneity. This reliable and reproducible method offers a practical framework for researchers to assess the performance of SERS substrates with simple instruments and techniques that should be easily available in a Raman spectroscopy laboratory.