Characterization of HPC‐based photoreduced SERS substrates and detection of different organic dyes

Abstract

AbstractSilver nanoparticles were fabricated in situ in the hydroxypropyl cellulose (HPC) matrix by irradiation at different wavelengths (365 and 254 nm) following the principles of green chemistry. HPC is involved in the silver reduction process and in the stabilization as well. Characteristics of the dispersions depend on the weight ratio between silver ions and HPC, irradiation time, and energy of the incident irradiation. Interaction at higher energies leads to higher degradation of the HPC matrix, resulting also in lower pH values of the dispersion. The latter is even more pronounced when using lower initial concentrations of silver nitrate. Different formulations were tested as surface‐enhanced Raman scattering (SERS) substrates with alizarin solutions and several other probes. Different spectral responses are related to different surface availability and/or to differences in microenvironment or macroenvironment of the nanoparticles. Substrates irradiated at lower energies show superior properties in terms of stability, whereas the substrates with a lower concentration of silver ions and irradiated with higher energies are more suitable for the detection of compounds with acidic properties (such as carminic acid and lac dye) due to lower electrostatic repulsion between the compounds and nanoparticles.