Determination of imidacloprid and triadimefon in white pine by gas chromatography mass spectrometry

Imidacloprid is one of a new class of highly systemic chloronicotinyl insecticides with significant activity against a wide range of insects. The triazole fungicides, triadimefon and triadimenol, are also systemic and highly effective in controlling a variety of economically important fungal diseases. A sensitive and reliable method for the determination of these compounds by GC/MS has been developed. Imidacloprid was converted to the heptafluorobutyryl derivative, whereas triadimefon and triadimenol were determined directly. Quantitation of all three analytes in white pine foliar extracts was performed in selected ion monitoring mode, by comparison with an external standard in sample matrix. Limits of quantitation were 0.01 ppm (10 pg injected) for imidacloprid and 0.1 ppm (100 pg injected) for both triadimefon and triadimenol. Overall mean recovery was 85.78 +/- 5.20% (6.06%). This method has been successfully applied to quantify in-planta residues after treatment of white pine seedlings with a controlled-release pellet containing imidacloprid and triadimefon for control of white pine weevil and white pine blister rust, respectively. Mean recoveries for QC samples were 85.62 +/- 9.34% (10.9%).