Determination Time of the Mononuclear Aluminum Species in the Hydroxyl Polyaluminum Solution by Ferron (7-iodine-8-hydroxyquinoline-5-sulfonic Acid)-Timed Spectrometry

A fixed time point on the curve of the absorbance variation with time determined in the hydroxyl polyaluminum solution by 7-iodine-8-hydroxyquinoline-5-sulfonic acid-timed spectrometry is usually used to quantify the mononuclear aluminum species in the hydroxyl polyaluminum solution. The right choice of the determining time of mononuclear Al must be established on the basis of the sufficient reaction between chromogenic reagent and the hydroxyl polyaluminum solution. But this question has never been noted, which resulted in the confusion of application and research of this assay. In this work, the effect of variation of the determining time on the accurate determination of mononuclear Al in the hydroxyl polyaluminum solution was first studied. The experimental results showed that 60 s was the best under the appropriate dosage of 7-iodine-8-hydroxyquinoline-5-sulfonic acid. The reasonableness of 60 s was further verified by 27Al nuclear magnetic resonance spectrometer and the absorbance–time curve obtained...