Abstract: The fluorescent reaction of salicylaldehyde salicyloylhydrazone (SASH) with indium (Ⅲ) was studied in detail. Based on this chelation reaction, a sensitive spectrofluorimetric method was developed for the determination of indium in a water-ethanol(volume ratio 3: 7) medium at pH 4.0. Under the condition, the InSASH complex displays an excitation and emission maxima at 396 and 461 nm, respectively. The linear range of the method is from 4. 7 to 1000 ng/mL and the detection limit is 0. 94 ng/mL. The molar ratio of indium to the reagent is 1 : 1. The interferences of other ions were studied. The method was successfully applied to the determination of indium in the chemical reagents of lead, tin, zinc, zinc chloride and geological samples by standard addition method.

Key words: Indium determination, Salicylaldehyde salicyloylhydrazone, Spectrofluorimetry