Ag dendritic nanostructures for rapid detection of thiram based on surface-enhanced Raman scattering

Abstract

Surface-enhanced Raman scattering (SERS) has been proven to be a powerful analytical tool for the detection of trace molecules owing to its integration of high sensitivity, unique spectroscopic fingerprint, and non-destructive data acquisition. However, the lack of reliable, stable, well-defined and uniform SERS substrates impedes their further practical applications in various fields. Herein, we have developed a SERS-active substrate based on Ag dendrites for sensitive Raman signal readout and trace detection of pesticide residues in agricultural products and environments. The SERS substrate can be employed to detect rhodamine 6G (R6G) with an enhancement factor (EF) of 3.18 × 10⁸ and the pesticide thiram in commercial grape juice with a detection limit of as low as 0.1 μM (0.03 ppm), which is much lower than the maximal residue limit (MRL) of 7 ppm in fruit prescribed by the U.S. Environmental Protection Agency (EPA). Furthermore, spiked detection indicated that the Ag dendritic substrate can be used to monitor thiram in commercial grape juice and natural lake water without further treatment.