<i>In situ</i> synthesis of low-cost and large-scale flexible metal nanoparticle–polymer composite films as highly sensitive SERS substrates for surface trace analysis

Abstract

Surface-enhanced Raman spectroscopy (SERS) has been one of the most promising analytical tools. Despite many efforts in the design of SERS substrates, it remains a great challenge for creating a general flexible substrate that could <i>in situ</i> detect analytes on diverse objects. Herein, we report our attempt to address this issue by developing a facile and versatile method capable of generating silver/gold nanoparticles <i>in situ</i> on the surface of a cellulose acetate (CA) polymer in a simple, cheap, practical, and capping agent-free way. The as-prepared substrates exhibit excellent sensitivity, which enabled detection of Rhodamine 6G at concentrations as low as 10^-12 M. Taking advantage of the excellent flexibility and optical transparency of the CA matrix, the highly SERS-active substrate was applied for <i>in situ</i> identification and detection of pesticide residues on fruits. The results indicated that tetramethylthiuram disulfide (TMTD) and thiabendazole (TBZ) can be clearly identified at concentrations as low as 18.05 ng cm^-2 and 15.1 ng cm^-2, respectively, which were much lower than the maximum permitted residue doses with respect to food safety.