Quantitative measurement captan and riadimefon residue by terahertz time-domain spectroscopy

Terahertz time-domain spectroscopy was used to measure terahertz far-infrared spectral characteristics of two pesticides (captan, riadimefon) at room temperature. From the experimental results, a series of characteristic absorption peaks can be observed between 0.2 THz and 3.0 THz. Comprehensive analysis of two pesticides absorption spectrum and refractive index of spectral features, we can find that their absorption and refractive index spectrum are very different. We have studied THz spectra of molecular forms of nitrofen based on the density functional theory (DFT). These feature absorption spectra are helpful to form a basis for pesticide spectral library.