Methods of detecting residual agricultural chemicals in rice
A study published in the Journal of Food Science examined the effectiveness and precision of using surface-enhanced Raman spectroscopy (SERS) to detect ediphenphos residue in rice.
A study published in the Journal of Food Science examined the effectiveness and precision of using surface-enhanced Raman spectroscopy (SERS) to detect ediphenphos residue in rice. Ediphenphos is a fungicide commonly used to prevent and control rice blast given its excellent inhibition of chitin synthesis and lipid metabolism. This fungicide can promote rice growth and increase yield; however, the inappropriate application of it causes ediphenphos residue to accumulate in rice and other agricultural products.
The researchers developed a simple pretreatment method for rice samples, and uniform gold nanorods were used as a substrate for SERS measurement. The researchers compared Raman spectroscopy and SERS of ediphenphos in different solvents and found that the rice extraction solution exerts no effect on the appearance of characteristic peaks, indicating that the SERS method can be applied for the preliminary detection of ediphenphos in rice. Characteristic signals can still be detected when ediphenphos concentration in rice extraction solution was higher than or equal to 0.1 mg/L.
The researchers conducted quantitative analysis of ediphenphos by regression models developed using partial least‐squares regression, random forest, and kernel principal component analysis. They found that the root‐mean‐square error of cross validation (RMSECV), coefficient of determination (R2), and relative predicted deviation (RPD) of optimal model were 0.022 mg/L, 0.9967, and 297.45, respectively, which indicated the proposed method can predict ediphenphos concentration with high precision.
To validate the feasibility of practical application further, rice samples spiked with 10, 5, 1, 0.5, and 0.1 μg/g ediphenphos residue were analyzed using the same method. The predicted recovery was in the range of 93.4% to 102%, and the predicted error was small for residue of each concentration. These results demonstrated that the presented method could be used for accurate and quantitative detection of ediphenphos residue in rice.