Femtomolar detection of thiram via SERS using silver nanocubes as an efficient substrate

Environmental remediation is a significant factor in maintaining a balance in nature. Pesticides are one of the main factors destroying nature by pollution and have hazardous effects on the environment and living systems. Thiram (TRM) is a fungicide used in agriculture and the rubber industry on a large scale. However, the excess use of TRM can cause harmful effects to living systems. Herein, silver nanocubes (Ag NCs) are demonstrated as an efficient substrate for the detection of TRM at ultra-low concentrations. Surface enhanced Raman scattering (SERS) is a highly sensitive technique employed for the ultra-low detection of TRM using Ag NCs. A shape-dependent comparative SERS study was carried out between Ag NCs and silver nanowires (Ag NWs), where different facets of the NCs and NWs were crucial for the creation of hotspots to enhance the detection limit. The enhancement factor (EF) for TRM with Ag NCs (TRM-Ag NCs) and TRM with Ag NWs (TRM-Ag NWs) was found to be 1.6 × 10 6 and 4.5 × 10 5 , respectively. The Ag NCs showed a 3.55-folds higher enhancement compared to the Ag NWs. Theoretical studies were carried out using the finite element method (FEM) to identify the hotspots, leading to an EF in the SERS signal in the Ag NCs and NWs, and the results were consistent with the experimental observations. The limit of detection (LOD) achieved was as low as 10 fM (0.002 ppt) for TRM-Ag NCs and 1 nM (0.25 ppb) for TRM-Ag NWs, which is inevitably beneficial to human health preventing contamination in the environment.