Multi-branched gold nanostars with fractal structure for SERS detection of the pesticide thiram

The surface-enhanced Raman scattering (SERS) activity of multi-branched gold nanostars with fractal structure has been investigated for trace detection of pesticide thiram. Raman spectrum results show that the gold nanostars substrate can produce about 10² fold stronger signal than the thiram alone with the thiram concentration increase of 10³ times and 1.4 fold stronger signal than the gold nanostars without fractal feature. In the detection procedure, the most prominent SERS peak at 1376 cm^{− 1} has been chosen to characterize and quantify the concentration of thiram. Experimental results indicate this Raman substrate based on fractal gold nanostars exhibits excellent selective probing performance for thiram with a detection limit as low as 10^{− 10} M in solution and 0.24 ng/cm² in apple peels. Interference experiment results show that the effects from the interfering pesticides could be neglected in the detection procedure. Therefore, the gold nanostars as a SERS substrate have excellent sensitivity and selectivity.