Determination of Tricyclazole Content in Paddy Rice by Surface Enhanced Raman Spectroscopy

Abstract: An ultrasensitive method based on Surface enhanced Raman scattering (SERS) has been developed to determine content of a pesticide which is tricyclazole in paddy rice using sliver colloid as a substrate and pyridine as an internal standard. The peaks at 424 and 1035 cm^?1 in a SERS spectrum were selected as analytic and internal peaks, respectively, and their intensity ratio I_t/I_p was used to calculate the regression concentration of tricyclazole. The correlation between I_t/I_p and concentration showed significant linear relationship with a correlation coefficient of R²= 0.995 in a concentration range of 0.05 to 0.70 mg/L and the tricyclazole solution can be detected to be low as 0.002 mg/L by SERS. The method was applied to determine tricyclazole contents of 3 real rice samples with a standard addition method in order to eliminate interference of matrix. The errors of SERS measurements for the 3 samples were 0.0008 to 0.0246, 0.0013 to 0.0028, and 0.0129 to 0.0304 mg/kg, respectively, compared with the results obtained by high performance liquid chromatography method. This also showed a good reproducibility with low values of relative standard deviation (n= 3) for the 3 samples ranged from 3.63% to 4.64%. Practical Application: SERS is a simple, rapid, and sensitive method to detect pesticides residue in agricultural food. Our results demonstrate that coupled with silver colloid, SERS is able to rapidly determine tricyclazole residue in paddy rice, indicating that SERS can provide rapid, accurate, and reproducible results for tricyclazole determination at trace level in paddy rice.