title: Determination of gibberellic acid residues on fruits by synchronous scanning derivative spectrofluorometry.
abstract: A synchronous derivative spectrofluorometric method is described for the determination of the plant growth regulator, gibberellic acid (GA3). The method is based on the formation of a fluorogen in concentrated sulfuric acid. The reaction is carried out at 85% sulfuric acid and in aqueous medium. The common fluorometric method with a linear dynamic range of 137-400 ppb, and a detection limit of 48 ppb is described. The synchronous first and second derivative method has linear dynamic ranges between 7.6-40 ppb and 12-40 ppb, with detection limits of 3.5 and 6.7 ppb, respectively. The influence of reaction variables and of other plant growth regulators present, and the application to residues on oranges, lemons, and grapes, are also described.
mesh_terms: D005638:Fruit / Q000032:analysis*; D005875:Gibberellins / Q000032:analysis*; D007202:Indicators and Reagents; D013050:Spectrometry, Fluorescence
chemical_list: D005875:Gibberellins; D007202:Indicators and Reagents; C007842:gibberellic acid