Abstract: | Abstract Trace amounts of metal ions which form stable complexes with EDTA at pH 4.0 have been titrated using morin as a fluorometric indicator. Back ticration of excess EDTA with Ga(III) and instrumental endpoint detection were employed for the determination of ions which are not normally determined by fluorometric methods. The continuous monitoring of the change in the fluorescence intensity throughout a deration also allowed mixtures of Ga(III) and In(III) to be determined when TTHA and EDTA were employed as double titrants. |