Determination and Identification of Daminozide in Fresh Fruits Purchased in Japan

The concentration of residual daminozide (trade name of formulation: Alar or B-Nine) in cherries, grapes, peaches, and apples purchased in Japan was investigated using the colorimetric method. Daminozide hydrolyzes in boiling strong alkaline solution to release unsymmetrical dimethylhydrazine which is distilled and reacted with trisodium pentacyanoamine ferroate to form a specific red color at pH 4.5. This color is measured spectrophotometrically. The levels of daminozide detected were 0.07–1.39 ppm in cherries (11 samples), 0–0.36 ppm in grapes (10 samples), 0–0.42 ppm in peaches (9 samples), and 0–0.88 ppm in apples (10 samples). Furthermore, daminozide in each sample was identified as methyl daminozide by the gas chromatography/mass spectrometry (GC/MS) method.