A Validated LC Method for Determination of Trace Impurities in Technical Triadimefon

A simple and sensitive liquid chromatography with ultraviolet detection (LC-UV) method was developed for the determination of three impurities with a content over 0.1% (w/w) in technical triadimefon. A Gemini C-18 column (5 mu m, 250 mm x 4.6 mm i.d.) was used for the chromatographic separations. The samples were separated by gradient elution with water (solvent A) and methanol (solvent B) using the following conditions: 70% A isocratic for 12 min, linear to 0% A within 8 min, and isocratic for 10 min at 0% A with a flow rate of 1.0 mL min(-1). Chromatograms were recorded at an absorption wavelength of 280 nm. The chromatographic resolutions between triadimefon and its potential impurities A, B, and C were greater than 3. The developed LC method was validated with respect to linearity, accuracy, precision, and robustness. This method was successfully applied to analyze the impurities in commercial technical triadimefon. In addition, the structures of the three impurities were identified to be (A) 4-chlorophenol, (B) 1-(2,4-dichlorophenoxy)-3,3-dimethyl-1-(1H-1,2,4-triazol-1-yl)-2-butanone, and (C) 1,1-bis(4-chlorophenoxy)-3,3-dimethyl-2-butanone.