DIFFERENCES BETWEEN INFRARED-SPECTRA OF ATRAZINE OBTAINED UNDER TRANSMITTANCE AND DIFFUSE REFLECTANCE MODES

We hypothesized that the surface amino-group of chloro-atrazine particles protonates when exposed to atmospheric moisture and therefore an outer layer of chloro-atrazine colloids was expected to transform to hydroxy-atrazine. To test the hypothesis we compared transmittance infrared (FT-IR) spectra with diffuse reflectance spectra of pure chloro- and hydroxy-atrazine under various treatments and two commercial forms of atrazine, AATREX-4L and AATREX-90. These spectral comparisons indicated that a certain number of chloro-atrazine molecules in the outer-layer of chloro-atrazine crystals transformed to protonated hydroxy-atrazine molecules. This is believed to have practical implications on the fate and mobility of atrazine in the field.