Antagonistic action regulated anti-etching colorimetric detection of thiram residue in soil based on triangular silver nanoplates

•The antagonistic action between thiram and I− on the etching of TSNPs was regulated.•An anti-etching colorimetric detection of thiram in soil based on TSNPs was proposed.•This method shows good anti-interference ability against other halide ions. The noble metal nanoparticles-based colorimetric detection can simply determine the concentration of the substances by naked eyes, but difficultly resolve the conflict between sensitivity and anti-interference ability. Herein, a triangular silver nanoplates (TSNPs)-based anti-etching colorimetric detection method for analyzing thiram was proposed by regulating the antagonistic action between the protection of thiram and the etching of I− on TSNPs. The internal mechanism of etching induced peak shift of TSNPs was revealed by the discrete dipole approximation method. The effect of thiram and I− on the color of TSNPs was systematically studied. As a consequence, this method not only shows a limit of detection of 19.7 nM in the linear range of 0.025−0.35 μM by absorption spectroscopy, but also produces sensitive color changes for the detection by naked eyes. Especially, it shows good selectivity that can resist the interference of other substances including other pesticides and halide ions in the specimens. It also shows excellent applicability in the detection of thiram residues in soil. This work provides a potential device-free strategy for the application of colorimetric detection in specimens with lots of interfering substances.