Signal detection limit of a portable Raman spectrometer for the SERS detection of gunshot residue

Signal detection limit (SDL), limit of detection (LOD), and limit of quantitation of a portable Raman spectrometer were measured for smokeless gunpowder stabilizers, diphenylamine (DPA) and ethyl centralite (EC), in acetone, acetonitrile, ethanol, and methanol. Acetone yielded the lowest LOD for three of four DPA peaks, and acetonitrile yielded the lowest LOD for two of three EC peaks and the remaining DPA peak. When gold nanoparticles were added to the DPA solutions in acetone and acetonitrile, statistically significant changes were observed (DPA peak position, full width at half maximum, and/or total area) and SDL was improved for the majority of all peaks in both solvents.