Highly sensitive gold nanoparticles-modified silver nanorod arrays for determination of methyl viologen

Gold nanoparticles-modified silver nanorod (AuNPs@AgNR) arrays were fabricated as surface-enhanced Raman spectroscopy (SERS) substrates. The coffee ring effect of the AuNPs @AgNR was explored as a preconcentration method for enriching the target analytes and increasing the hot spots. Furthermore, methyl viologen (MV) as a toxic herbicide used in agricultural production was successfully determined to investigate the application of the coffee ring effect on AuNPs@AgNR arrays and density functional theory (DFT) was employed to calculate its vibrational modes of corresponding characteristic peaks. Good linearity was obtained in the range 0.10-100 mg/L, and the limit of detection (LOD) of MV was estimated to be 0.01 mg/L, which was lower than the US maximum residue limits (MRLs). This method was also applied to practical detection of MV in river water and apple peel with LODs of 0.10 mg/L and 0.05 mg/L, respectively. SERS results suggest that the coffee ring on AuNPs@AgNR arrays provides a promising way for monitoring environmental pollution and food safety caused by pesticides.

Automated summary

In this study, gold nanoparticles-modified silver nanorod arrays were used as surface-enhanced Raman spectroscopy (SERS) substrates. The coffee ring effect of the arrays was explored as a preconcentration method for target analytes. Methyl viologen, a toxic herbicide, was successfully determined using this method. The results suggest that the coffee ring on the arrays provides a promising way for monitoring environmental pollution and food safety caused by pesticides.