The danger of dichloromethane in the synthesis and application of imidazole-based dyes

In this paper, a lophine-based phenol compound has been prepared and identified as an efficient chromophore for the determination of hydrogen peroxide (H 2 O 2 ) with enzymatic method. A dry chemistry analytic agent was also prepared involving this compound, showing good accuracy in the determination of uric acid. However, a commonly used solvent dichloromethane (DCM) could react with this imidazole derivative when the reaction mixture was irradiated under UV (365 nm). We explored the possible mechanism and identified several by-products caused by the acidity and ultraviolet oxidation of DCM. Caution should be taken in the synthesis and application of such imidazole-based dyes in DCM, especially when phenol group was introduced to the imidazole moiety.