A pH Sensor Based on Surface-Enhanced Raman Scattering

摘要

Surface-Enhanced Raman scattering sensor is being developed for facile applications in biological and environmental fields. Its advantages including portable spectrometer and ability of point-of-care detection will benefit the real-time analysis. We investigated the SERS response to the pH value in solutions. It was found that in acidic solution, the hydrogen bond interaction will bring AuNPs together, resulting in the aggregation of AuNPs. After aggregation of AuNPs, the solution became purple from wine-red. This color response inspired the present system to be colorimetric sensor for the rough detection of pH values. Furthermore, the intensity of Raman peak increases with the pH value change from alkalinity to acidity. It was concluded that Raman signal of p-MBA adsorbed onto AuNPs can be used to indicate the pH value in solutions.