Surface-enhanced Raman scattering from an etched polymer substrate

An etched polymer was evaluated as a substrate suitable for routine SER analysis and was found to perform similarly to crossed gratings and posted quartz wafers. Silver particles were layered onto sheets of etched poly(ethylene terephthalate) by chemical reduction, sputtering, and vapor deposition. Enhancement factors ranged from 10(4) to >10(5) for crystal violet on chemically reduced and sputtered surfaces, respectively. Ranges of linearity up to 3 orders of magnitude were attained with limits of detection of ∼5 pg. The variability of response was <20% RSD for both routinely and painstakingly prepared samples. To induce enhancements beyond those possible from the dry substrate, a thin film of water was held on the analyte-treated substrate surface in a liquid state. Typical spectra of nine analytes with amino, carboxylate, and/or nitro groups were collected from the most active substrate.