The method of indolo-.alpha.-pyrone fluorescence-determination of IAA was investigated to study possible interference from 4-chloro-indoleacetic acid and 5-hydroxyindoleacetic acid, which occur naturally. Both compounds show about 40% of the fluorescence of IAA after conversion into their .alpha.-pyrones. Other halogenated indoleacetic acids show between zero and 60% of the fluorescence of IAA. Apparently the concentration of IAA cannot be determined in crude extracts in the presence of 4-chloro- or 5-hydroxy-indoleacetic acid, because separate determinations of each of these compounds are not possible by changing the excitation or fluorescence wave-lengths of the testing equipment.
|Publication status||Published - 1978|