Paper-based SERS chips for the rapid detection of thiram

A simple one-pot method is developed to prepare positively charged aggregated silver nanoparticles (a-AgNPs). The obtained a-AgNPs show strong localized surface plasmon resonance (LSPR) absorption, whose wavelength can be easily tuned to match the commonly used lasers in surface enhanced Raman scattering (SERS). Furthermore, the obtained a-AgNPs can be easily fabricated into paper-based SERS chips by filtering against a negatively charged filter membrane. On the basis, a convenient SERS sensor has been developed for the detection of thiram using a 785 nm handheld Raman spectrometer.