Evaluation of the Reliability of Six Commercial SERS Substrates

Based on high sensitivity, specific fingerprinting spectra and real-time detection, surface-enhanced Raman spectroscopy (SERS) is a powerful tool for the observation, the detection and the identification of chemical or biological species at low concentrations. One of the key elements for the SERS detection is the choice of SERS substrate. This latter one can be either a home-made one or either commercially purchased. For researchers who don’t have facilities to fabricate SERS substrates, the commercial ones are a necessary and optimal choice. Thus, a comprehensive evaluation of their reproducibility is urgently needed and carried out in this paper. The blank spectra as well as the SERS spectra of three probes molecules (4-mercaptobenzoic acid (4-MBA), 1, 2-bis (4-pyridyl) ethylene (BPE) and methylene blue (MB)) were analysed for two excitation wavelengths (532 and 785 nm). The most suitable detection condition was determined for each substrate. Under the optimum conditions, the SERS mapping were carried to measure the relative standard deviations (RSDs) to further evaluate the reproducibility of the substrates. The results demonstrated that the Enspectrc, Q-SERS TM and Hamamatsu substrates were the more suitable for reproducible SERS measurements.