Flexible surface-enhanced Raman scattering substrate of cotton swab-Ag combination with smartphone app for chemical warfare agent simulants detection

Abstract

A simple method was developed for the one-step synthesis of silver nanoparticles (AgNPs), co-stabilized by poly[N-(3-trimethoxysilylpropyl)diethylenetriamine] (PATS) and embedded on a flexible cotton swab (CS). PATS served as the capping agent for AgNPs. The flexible CS-PATS-AgNPs substrate was subjected to surface-enhanced Raman scattering (SERS) for the detection of single and multiple chemical warfare agent simulants (CWAS). SERS peak intensity versus concentration changes were rapidly detected and analyzed using a self-developed smartphone-based app system, which performs quantitative detection of the analyte. The results showed that CWAS (dimethyl methylphosphonate, DMMP; 2-chloroethylethylsulfide, 2-CEES; acetonitrile, ACN can be detected with a high sensitivity, with a limit of detection (LOD) of DMMP, 2-CEES and ACN was 1.0, 46.7 and 57.9 g/L, respectively. The flexible SERS substrate, CS-PATS-AgNPs, in conjunction with a Raman spectrometer and a smartphone-based app system, possesses practical applications primarily owing to the low cost and simple sampling technique.