Aims and Objective: Pesticide residues seriously affect human health, so it is very important to
study the degradation of pesticide residues for food safety. The degradation of pyridaben by ultraviolet
(UV) irradiation was studied, the degradation characteristics and modeling were analyzed in this paper.
This study was undertaken to fully reveal the degradation mechanism of UV irradiation for pyridaben
residue and provided the evaluation method of degradation effect.
Materials and Methods: Firstly, the fluorescence spectra of pyridaben samples were measured by LS55
fluorescence photometer, and the relationship between pyridaben concentration and the fluorescence
intensity of characteristic peak was established. Then, using UV irradiation approach, the pyridaben was
degraded to different degrees by controlling the irradiation time. The degradation process was
characterized according to the change of fluorescence characteristic peak intensity before and after
degradation. The relationship between degradation time and fluorescence intensity was established at last.
Results: The results showed that the fluorescence characteristic peak of pyridaben was located at 356 nm.
The pyridaben content prediction model function was obtained with the correlation coefficient of 0.9989
and the average recovery of 99.70%. The relative standard deviation (RSD%), the limit of detection (LOD)
and the limit of quantity (LOQ) was 1.71%, 0.0058 ug/ml and 0.0193 ug/ml, respectively. The exponential
function model between UV degradation time and fluorescence intensity was obtained, the corresponding
correlation coefficient was 0.9991, and the average recovery was 100.49%.
Conclusion: UV light irradiation can effectively degrade pyridaben, degradation process can be
characterized by the change of fluorescence intensity, and the degradation model was tested to be accurate.