ANALYSIS FOR DAMINOZIDE IN APPLE JUICE BY ANION-EXCHANGE CHROMATOGRAPHY PARTICLE BEAM MASS-SPECTROMETRY

Daminozide [Alar, succinic acid mono(2,2-dimethylhydrazide)] is measured directly as the parent compound in 11 commercially obtained apple juice samples at levels ranging from 0 to 280 ppb (average 160 ppb). Sample preparation involves only evaporation and treatment with methanol and acetone to precipitate sugars and inorganic salts. Analysis is via anion-exchange chromatography particle beam mass spectrometry, with positive chemical ionization using isobutane as a reagent gas. A method detection limit of 25 ppb is achieved in part by a signal enhancement resulting from the constant addition of 0.4 mM malic acid to the mobile phase. Malic acid also modifies the nature of the mass spectrometer response to daminozide, changing it from a nearly cubic to a linear relationship and also changing relative ion intensities, between the base ion of M + 1-H2O without and M + 1 with 0.4 mM malic acid. © 1990, American Chemical Society. All rights reserved.